Hardly anyone loves the Y-Wing. The early-Clone Wars-era-relic is subject to online ridicule, and no one dresses up as a Y-Wing pilot at cons. When introduced to fans in the first Star Wars movie, it was basically fodder for TIE fighters to blow up in order to emphasize to the audience how deadly the baddies could be, and how awesome Luke and the X-Wing were. Over the years, between the prequel trilogy, Clone Wars cartoons, and other canon, a much larger body of lore about the Y-Wing has emerged.
As an defense analyst, and former Naval aviator, I evaluate programs and weapons systems that the DOD is considering procuring. While the Department of Defense doesn’t always listen to us when we recommend which system to buy, we make these decision based on what we believe the “best” option for the service is, based not only on how combat effective a system is at entry, but based on a wide variety of other factors including reliability, maintainability, life cycle costs, training, logistics, what facilities are needed to support the platform, and how well the system fits with current doctrine. The military even has an acronym for the trade space of solutions evaluated: DOTMLPF (doctrine, organization, training, materiel, leadership and education, personnel, and facilities — pronounced “dot-mil-p-f”)
So, is the Y-Wing a “bad” weapons system? This is a bit like asking if the B-52, KC-135, UH-60, A-10, F-15, or other older systems are bad because they have become less and less survivable as the battlespace has evolved. Other aircraft, like the PBY Catalina and B-52, managed to stay in service well past their expiration date and outlast the models meant to replace them. There are reasons why some weapons systems remain in service for 70 years or more, and others are phased out rapidly (B-58 Hustler, F7U Cutlass) in less than a decade.
In general, though, systems which have extremely long service lives aren’t considered to be awful: rather they are generally judged to be the great success stories of military design and procurement. There are usually several key areas where they did very well that allowed them to stay in service for so long.
So, let’s explore what allowed the venerable Y-Wing to stay in service for over 50 years, and why these provide strong evidence that the Y-Wing did not, in fact, “suck”.
(Note: this analysis is based on canon where possible, and literally hundreds of hours in college spent playing X-Wing and X-Wing vs. TIE, and my background as a defense analyst where all else fails.)
At the start of the Clone Wars, the Republic had just stood up its fleet, was outnumbered by the separatist droid armies, and was generally just trying to hold on to what it had. They had very few options for a fleet fighter at the time, namely the V-19 Torrent, Delta 7 light interceptor, and the BTL-B Y-Wing. The Delta 7 was ill-suited to large scale space warfare; it lacked an internal hyperdrive, shields, payload, and was so difficult to fly that the only humans who could control it effectively were Jedi. Despite entering service the same year (22 BBY) as the Y-Wing, the V-19 lacked shields, had no hyperdrive (initially), had less payload than the Y-Wing, and was generally considered a “rush-job” to get something into the fleet that could be mass produced and flown by hastily trained clone troopers.
The Republic was mostly on the defensive at the start, and relied on the sort of “hit and fade” tactics that characterized the rebellion two decades later. At the start of the Clone Wars, the Y-Wing was state of the art. It was clearly a better option for deep-strike hit-and-run tactics than the other two alternatives, both of which required hyperdrive rings to travel interstellar distances. This prevented the V-19 and Delta 7 from quickly and easily escaping after their missions. With heavier armor, hyperdrive, large missile payloads, and shields, the Y-Wing was far better suited to the doctrine of the early-War Republic. This was why it was chosen by General Anakin Skywalker for the surprise long-range strike on the Subjugator-class heavy cruiser Malevolence early in the war.
Unlike the ARC-170 heavy starfighter, which replaced the V-19 and partially supplanted the Y-Wing during the Clone Wars, the BTL-B had ion cannons, which allowed them to disable ships without destroying them or killing those on board. “Acquiring” supplies, stealing ships, and liberating prisoners were all frequent missions of the early rebellion. Without the logistic support of allied worlds, stealing supplies from the Empire and hit and fade tactics weren’t just preferred — they were the only feasible options. Ion cannons facilitated all of these missions, and were usually necessary when boarding non-cooperative ships.
Thus, the Y-wing was also well suited to the beginning of the rebellion, and better suited than the newer ARC-170. In many cases it was better suited than the newer X-Wing or A-Wings because of it’s ion cannon. These same characteristics that made the Y-Wing a viable option during the Rebellion were again necessary during the fight with the First Order, and the collapse of the New Republic.
The organization of Y-Wing squadrons, and the tactics and doctrine of employing them, changed over time. During the early years of the Clone Wars, the Y-Wing did an acceptable enough job in the role of a fighter that was capable of what the military calls ”self-escort.” As time went by, and ships grew faster, escort duties and space-superiority missions more commonly went to the Z-95 Headhunter multi-role fighter, and later to the smaller V-Wing starfighter. The Z-95 had shields, but lacked hyperdrive initially, making it a poor choice to escort Y-Wings on long range missions. The V-Wing was much like the Delta 7 Jedi interceptor in terms of armaments, speed, and maneuverability, but was pilotable by clones and non-force sensitive humans. Unlike the phased-out V-19 (but similar to the Z-95), the V-Wing had shields, but still lacked an internal hyperdrive, reducing its effectiveness and survivability on escort missions as well.
A precursor to the A-Wing had been in development at the end of the Clone Wars to address the issues of the V-Wing as a platform with speed, maneuverability, shields, and an internal hyperdrive. However, the R-22 prototype was completed too late to see service. However, the pairing of A-Wings and Y-Wings early in the Rebellion was a continuation of the doctrine and organization of Y-Wing units during the latter parts of the Clone Wars. What changed, primarily, was organizing small units of Y-Wings for hit and fade missions, to operate with similarly hyperdrive equipped escort fighters. Planning for this had been in the works at the end of the Clone Wars, and resurrecting old ideas is not new to the military: the U.S. Navy arsenal ship concept just keeps coming back.
The A-Wing was not ideal for longer range strike missions, being difficult to fly, lacking an astromech droid for navigation and autopilot duties, having a cramped cockpit, and having mechanical reliability issues.
As the Rebellion grew, there were more attacks on capital ships, allowing Y-Wings to operate in larger squadrons (rather than small or 3-ship formations) acting as mobile proton-torpedo launchers that drop in, get within range, launch, and leave as quickly as possible. This isn’t too different from how modern B-52s are used as “trucks” to get to the edge of the weapon envelope and fire swarms of cruise missiles. Also like the Y-Wing, at the beginning of the B-52’s career it was expected to go “downtown”. However, as defenses advanced both platforms adapted to new roles that exploited their payload, versatility, and range to deploy long range weaponry in large volumes against well defended targets.
Compared with the TIE Bomber in this role, Y-Wings were more survivable (having shields, more armor before retrofit, a hyperdrive, and heavier structure), faster, and better suited to defend themselves in a pinch if the fighter escort “leaked”. Again, the versatility of the Y-Wing allowed it to function within different organizational structures and support doctrines that changed as the course of the war did.
The Star Wars universe doesn’t speak directly to this, but we can make inferences. How the Y-Wing was used suggests that it was relatively simple and easy to fly compared with the ARC-170 (which required a minimum of three people to fly). The deletion of the second crew member in later models further suggests that the pilot was not task saturated by the star fighter and its human-machine interface. They face that Y-Wings soldiered on in the Outer Rim and with various and assorted planetary defense forces, private mercenary corps, and even pirate forces suggests simplicity, and that acquiring legacy simulators, instructors, and training materials wasn’t too difficult, especially with so many cashiered clone pilots looking for work after the Empire got out of the cloning business.
On the flip side, such training infrastructure had to be built from the ground up with the A-Wing, X-Wing, and B-Wing. There’s a reason why canon says that pilots usually started in the Y-Wing, and then graduated to either A-Wing or X-Wing: the first plane new Navy pilots strap into isn’t an F-35C, it’s a turboprop that flies a lot like a P-51 Mustang. For decades Air Force pilots started on the jet-powered, versatile, simple, but slow and forgiving T-37 “Tweet”. Although hopeless as fighters, either is capable in the Close Air Support (CAS) or ground attack role. Similarly, the World War II era P-47 Thunderbolt and Vought F4U Corsair started as capable fighter-bombers but ended their successful careers primarily as ground attack aircraft, particularly in Korea where the Corsair was outclassed badly by the new Soviet MiG-15s they faced.
Material means all the “stuff” (weapons, spares, support equipment, etc.) needed to support operations, excluding personnel. In this regard, the Y-Wing is the clear winner among snub-fighters of the rebellion. After the Clone Wars the Y-Wing and the ARC-170 were the dominant strike fighters of the era. The Empire quickly divested itself of both as its fleet tactics changed. The Imperial fleet paradigm switched to amassing armadas of large capital ships defended by swarms of small fighters, such as V-Wings and the original TIEs. These fleets would jump into systems en masse and overwhelm any conceivable opposition. Hyperdrive-equipped fighters like the ARC-170 and Y-Wing did not fit in with this new strategy.
Given a vast surplus of fighters after a great conflict, the Empire had three options: sell them, scrap them, or store them for a future conflict. It appears that the Empire found buyers for at least some of their massive fleet of used BTL-B Y-Wings, but not so with the complicated, expensive, crew intensive ARC-170. This may not make sense on the surface, but remember that the Empire emerged from the Clone Wars in desperate economic straits. Selling war surplus in dribs and drabs to entities that couldn’t hope to threaten (at the time) Imperial capital ships may have been a way to quickly draw down and deal with the overwhelming debt of financing the war.
Koensayr (the manufacturer of the Y-Wing), and Incom (manufacturer of the ARC-170, Z-95, and later the X-Wing) both emerged from the Clone Wars with massive manufacturing infrastructure on their hands, as well as substantial unsold stock in parts and partially built Y-Wings and ARC-170s. Koensayr apparently was able to find continued buyers of the Y-Wing. Incom apparently could not for the ARC-170, and the Z-95 was already obsolete, being the oldest of the designs. Manufacturing a new fighter requires building out factories (e.g. land, buildings, machinery, tools, dies, etc…) and other infrastructure (e.g. parts supply chains). Going into the Rebellion, Koensayr likely had these in place for resuming large scale production of the Y-Wing. Incom was likely still ramping it up for the X-Wing.
As a result, Y-Wings emerged from the conflict the dominant multi-role fighter available to planets for self-defense, guilds for convoy protection missions, and even general policing duties in a system using their ion canons. Spares were plentiful, with both aftermarket parts and ones cannibalized from boneyards and salvaged craft being widely available. Everything else needed to support operating Y-Wings could also likely be acquired cheaply and easily.
Contrast this with the X-Wing, A-Wing, and B-Wing. None of these had existing aftermarkets, logistics supply chains, or boneyards. Parts and support equipment for these craft would have been difficult to find except through new parts and craft coming off the line, and likely only from the original manufacturers. It is impossible to overstate the value of having a robust logistics supply line and access to functional support equipment to enable operations. A functional Y-Wing is infinitely more valuable to the Rebellion than an X-Wing that is non-mission capable for spares, or an A-Wing whose engines won’t light off because the start cart replacement won’t arrive for another three weeks (assuming that the Empire doesn’t find and seize the shipment en route.) In both these cases, you have a paperweight taking up valuable hangar space.
In real life, there’s a reason why you can still find parts for, and maintain, aircraft dating to the 50’s. It is possible keep them in service with second-line nations around the world. Israel operated the robust, versatile, mass produced little A-4 Skyhawk until 2015, and Argentina still does. Because so many were built during the Cold War, and you can still find parts relatively easily.
Personnel refers to anyone required to operate the system. This includes pilots, maintainers, logisticians, mission planners, and anyone else necessary to making the mission happen. In the real world, personnel and fuel tend to be the two biggest reasons why Air Forces collapse during sustained conflicts. After the Clone Wars, there were a substantial number of people who knew how to operate, maintain, support, and utilize either the Y-Wing or ARC-170 operationally. However, the Y-Wing was clearly the better choice among what is immediately available.
Though both the Y-Wing and the ARC-170 were available as surplus and salvage after the war, the latter needed three times as many flight-crew members to operate, while being only marginally more survivable. Whenever a smaller adversary must fight a larger opponent, they have to rely on lopsided kill ratios to win. Given that crew members are the hardest part of the starfighter to replace, the Y-Wing was a far better choice than the ARC-170 for what the Rebellion should choose “off the shelf” as a long-range fighter bomber.
While the Y-Wing was less survivable than the fast and nimble (but poorly shielded) A-Wing, and the legendary X-Wing space superiority fighter, it was a reasonably survivable spacecraft when used properly. The Y-Wing was still effective as a long-range reconnaissance craft, as missile barges against capital ships, or a commerce raider against poorly defended targets. Under normal circumstances, its combination of shields and internal hyperdrive allowed pilots with good situational awareness to recognize when they were in over their heads and jump out to safety. It was only when the ship was pressed into staying and fighting against hordes of TIE fighters at battles (like Yavin and Endor) that they suffered heavy casualties.
Thus, the Y-Wing was better than the alternative (the ARC-170) when it came to protecting the Rebellion’s most valuable resource: its pilots. Training new pilots to a high level of competence requires a great deal of time, money, fuel, and effort. The outnumbered Luftwaffe and IJN pilots of Japan generally bested the Allies during the early years of the war, but over time they simply could not train pilots fast enough or effectively enough to overcome their losses, and the kill ratio shifted dramatically as WWII wore on.
It is also worth pointing out that the Rebellion was so badly outnumbered that there was not an option to simply use A-Wings, X-Wings, or B-Wings instead of Y-Wings. These ships were just coming into service, existed in very limited numbers, and production was still ramping up. All three were also more difficult and costly to manufacture. Y-Wings, and trained pilots, were available in larger quantities at that time.
The B-Wing was intended as a replacement for the Y-Wing yet was not suited for dogfighting either. It provided only slightly more survivability than its predecessor, which is usually the main argument against the BTL-A4. It’s also worth noting that the Y-Wing had 50% more shielding than a T-65B X-Wing, and could divert as much power from weapons to shields, allowing them take a hits, while preparing for the jump to hyperspace. Y-Wings were far better than nothing, particularly on missions requiring disabling fire or large volleys of proton torpedoes.
While DOTMLPF analysis looks at the viability of a system from a high-level organizational standpoint, it does not look as deeply at the platform itself. When doing an Analysis of Alternatives on various systems, you have to take into consideration such attributes as reliability, maintainability, cost, versatility, engineering space for growth, and performance. While the Y-Wing suffers in the performance department compared with other fighters of the Rebellion, it actually shines in the other areas.
Reliability / Maintainability
Weapons systems are useless if they can’t fight. In fact, they can be of net negative value if you’re spending excessive amounts of time, money, and manpower keeping them in a mission-capable state of readiness. There is always a trade-off: the people and money spent keeping a system going could also be used for other tasks.
Reliability involves how often a system “breaks”. Complicated systems with lots of moving parts are less reliable. So are bleeding edge high performance systems designed to push the edge of engineering margins squeeze out every last ounce of performance without wasting a single ounce of weight or cubic inch of space. While the age, wear and tear, and flight hours on Y-Wing frames increased the number of maintenance actions needed, the simplicity, robustness, system redundancy, and design maturity work in its favor, meaning less maintenance than other platforms of similar age.
Maintainability involves how easy it is to keep a system operationally ready. This involves already discussed factors like parts availability, training for maintainers, and how easy it is to find people with experience working on a system. It also involves things like system complexity, compactness, and how difficult it is to replace components within the weapon system.
The Y-Wing is the clear winner in both reliability and maintainability when compared with other Rebellion fighters. With the Clone Wars-vintage armor plating stripped off, the Y-Wing gave easy access to most systems on the ship. For reasons already discussed, the Y-Wing had far better access to spares and trained maintainers. It was generally reliable, despite its age. Koensayr had decades to work out most of the bugs in the design.
Conversely the A-Wing had poor reliability due to trying to cram as much capability into as small a space as possible, which also made it more difficult to maintain. The X-Wing and B-Wing had the complicated moving foil system. Working on the B-Wing could be a nightmare, given how difficult it was to reach certain component while the craft was on the ground. They were also newer, meaning that it is likely early operations were revealing design issues that would need to be fixed on later models.
The cost of a system isn’t just how much it takes to buy it. The total Life Cycle Cost of a system also includes research and development (R&D) procurement, operation, support, and disposal. For military aircraft with an expected 30-year life, the rule of thumb for Life Cycle Cost Estimation is that 10% of total cost is R&D, 30% is procurement (unit cost), and 60% of total cost is for operations, support, and disposal. With this in mind, let’s discuss why the Y-Wing was the hands down winner in terms of cost.
The costs listed above are only the cost of buying the spacecraft. These are somewhat misleading. Virtually any Y-Wing during the Galactic Civil War was going to be used, but demand for the other Rebel fighters was such that finding a used A-Wing, B-Wing, or X-Wing was highly unlikely: the Alliance was buying them as fast as they could be manufactured. In fact, the real cost of Y-Wing’s was frequently zero. Rebels could simply steal them from poorly defended Imperial surplus storage facilities.
R&D costs for the Y-Wing were also effectively zero. Koensayr had been paid by the Republic for the R&D costs decades ago. When bought second hand, the seller is not trying to recoup R&D costs either. Stealing them also means no R&D cost.
Thus, assuming that O&S costs are based on the “new” price of a ship, we can see Life Cycle Costs (LCC) to the Rebellion based on an expected 30-year life of each ship using the 10/30/60 rule of thumb in the figure above. This is a conservative estimate, as it doesn’t take into account the Y-Wing’s fuel recycling capability that gave the BTL-B, and particularly the BTL-S3 versions, the long range needed for the deep strike and reconnaissance missions they were designed for. Nor does it account for the fact that the support equipment and spares for the Y-Wing can also be acquired more cheaply used, aftermarket, or just stolen from scrapyards than parts could be for newer models that required more reputable supply chains.
Based on this table, we can see that the expected relative cost of alternatives to the Y-Wing. Using the ratios shown, and the proton torpedo magazine capacities of the B-Wing (12) and the Y-Wing (8), it works out that for a fixed cost a group of Y-Wings can put out almost 50% more missiles in a sortie. In other words, Y-Wings are a significantly more cost-effective solution to the hit-and-fade missile-firing strike bomber role, and also significantly cheaper filling the role of ion-cannon platform for disabling fire in support of boarding actions.
Even during the Resistance War against the First Order, the Y-Wing remained a more cost effective, capable, and survivable alternative to the large, slow, vulnerable, costly, and ill-conceived MG-100 StarFortress. This monstrosity cost 350,000 Galactic credits, and killed five valuable crew members every time one was lost. They lacked the Y-Wing’s ability to accelerate to the edge of the launch envelope, ripple off their weapons, and retreat back within the covering fire of allied capital ships, or quickly hyperspace jump to safety after launching their ordnance.
Adaptability / Versatility
Military craft which only do one thing well, or complexly rely on one mission concept, rarely have long and successful careers. The ultra-fast B-58 Hustler only had one thing going for it in life: it went very fast. But, as Soviet air defenses improved enough to make it vulnerable, its short range and high operating costs doomed the otherwise beautiful plane, and it was withdrawn from service in only 10 years. Conversely, aircraft which do many things well, and have the space and power to act as “trucks”, last a very long time as their payload capacity allows them to take on different missions and equipment over time. The B-52 Stratofortress, UH-1 “Huey”, and PBY Catalina have all had exceptionally long careers based on their simplicity, reliability, robustness, payload, adaptability, and versatility.
The Y-Wing remained in service for so long because it was something of a truck. It could employ a wide variety of munitions, carried a mixed armament of lasers and ion cannons, possessed good range and good hyperspace speed, had better than average shielding, acceptable maneuverability for basic purposes of survival, and had wide engineering tolerances for new systems or modifications. Throughout its life, the BTL Y-Wing series was modified repeatedly Rebel engineers and maintainers to adapt it to function in an environment where the threats and missions were constantly evolving.
Over time they removed armor plating and the gunner’s seat from the BTL-A4 (the version most commonly used by the Rebellion) to improve speed. They re-routed engine power to improve maneuverability as the “meta” of the war shifted to an increased emphasis on fast, maneuverable fighters to deal with (and survive) TIE interceptors and the TIE advanced. They also removed the Y-Wing’s fuel reclamation system, increasing speed and maneuverability at the expense of fuel efficiency and range. The torpedo magazine was reduced by two to reduce weight, increase speed and maneuverability, and provide additional space within the frame. This improved survivability, and the Y-Wing still retained its best feature: shields with a SBD rating of 75.
The Y-Wing was designed with enough “surplus” power and space to allow changes and modifications that were almost modular: making one change to the craft didn’t require altering nearly everything else in the ship as well to keep the systems working together, as was an issue with the A-Wing, whose engineering was as over-complicated and touchy as a British race car.
Mobility is the ability to get to where you need to be. The Y-Wing was far ahead of its time here. It’s Class 1 hyperdrive made it one of the fastest ships in hyperspace during the Clone Wars. During the Galactic Civil War, this speed was still good enough for it to keep up with other Rebel fighters past light speed, and able to outrun most Imperial ships. Only a few highly specialized ship were faster than Rebel fighters in general. The other piece of mobility is range and endurance. The Y-Wing had good-to-great range, depending on whether the fuel reclamation system was left in place.
This meant that the Y-Wing, along with the X-Wing, could show up unannounced almost anywhere, complete their mission, and get out faster than the opposition could respond. It was fully capable of implementing the overriding principle of Rebel combat operations: “He who defends everything, defends nothing.” This philosophy of forcing the Empire to try and defend everything led them to become spread far too thin, and as a result more and more extreme measures to crack down on the Rebellion, thus driving even more worlds onto the side of the Alliance.
Was the Y-Wing the best at carrying out this doctrine? Of course not. But more importantly, the Y-Wings capabilities fit with Rebel doctrine, concept of operations, strategy, and tactics despite having been designed almost two decades earlier. The X-Wing and B-Wing were a response to current needs: the Y-Wing had effectively anticipated them.
Was the Y-Wing’s Longevity Good Luck or Good Design?
Much of the Y-Wing’s ubiquity, availability, desirability, and success during the Rebellion and Galactic Civil War stems from the simple fact (and perhaps good luck) that they were built in massive numbers in the Clone Wars. These ended suddenly, leaving a glut of surplus Y-Wings. Thus, if they had been built in much smaller numbers, or the Clone Wars hadn’t happened, would they still be considered among the “greats”? Was the longevity of this starfighter more a product of luck at coming about at just the right time and place to be built in vast numbers, or was it more a result of great design and foresight by the engineers at Koensayr?
Undoubtedly there was some luck involved. However, that luck didn’t carry through to any of the other innumerable types of fighters used by the Republic during the Clone Wars (e.g. V-19, V-Wing, Z-95, Delta 7) because the Y-Wing was simply a better design. The flour basic reasons why the Y-Wing soldiered on were its shields, hyperdrive, ion cannon secondary armament, and simplicity to operate and fly compared to the ARC-170. The only other fighter with shields and hyperdrive to match the Y-Wing was the ARC, but its need for three crew members and how difficult it was to operate made it more expensive and more difficult to field.
The ion cannon was simply the cherry on the top: giving it the ability to support boarding operations more effectively. Even some of the simple design choices made the Y-Wing more effective, such as mounting both lasers close together in line with the pilot and concentrating firepower. This rewarded good marksmanship, ensuring if one blaster hit, they both did. This was usually enough to one-shot a TIE/ln. In a X-Wing or B-Wing, the widely spaced cannons reduced firepower concentration against small targets in a dogfight. Even in WWII, mounting machine guns and cannons close together in the nose was considered an advantage in fighters like the P-38.
If there hadn’t been a Clone War, the Y-Wing would have found buyers among planetary police forces space coast guards, unions and guilds looking to provide escort for convoys, local defense forces that needed a counter to smaller capital ships, and (especially) pirates who would likely use the vessels the same way the Rebels did later. In short, the Y-wing possessed qualities that guaranteed someone would have bought and used it. And if it hadn’t existed, something similar would likely have been designed. There was clearly a trade space, or niche, for the Y-Wing to operate it between the roles filled by the A-Wing (point defense space dominance), X-Wing (space superiority), and B-Wing (expensive super-heavy assault craft).
In the final analysis, the Y-Wing would not have had such a long career without solid engineering behind it. Luck will only get you so far before you actually have to be good at something.
The Final Verdict
The Y-Wing was a phenomenal ship when it was designed. It was the only fighter design to last all the way through the Clone Wars in front line service. In World War II, only a few fighters achieved this feat (P-38 lightning, ME-109, Supermarine Spitfire) and all are considered among the greatest designs of the period. It continued to serve on alongside craft that were supposed to replace it, but proved too cheap, durable, and effective to replace entirely, much as the PBY Catalina remains in service as a water-bomber 85 years past its first flight, and decades after its supposed successors were retired.
The argument that the Y-Wing was a terrible ship because it was too slow and wasn’t maneuverable enough during the Galactic Civil war is an unfair assessment. The Vought F4U Corsair and North American P-51 Mustang were among the best fighters in World War II, but too slow to defend themselves from Russian piloted MiG-15 jets during the Korean War only five years later. They still did great work as close air support fighter-bombers in Korea based on their endurance, range, payload, and (in the case of the F4U) rugged construction and survivability. Both are still considered some of the best combat aircraft ever made, despite their obsolescence later in their service lives. Thus, the Y-Wing is being held to a different historical standard than other platforms.
The fact that the Y-Wing still played a pivotal role as a front line starfighter in a war 20 years after it entered service is a testament to how forward-looking its design was in many ways. It had a niche as a cheap, effective, survivable fighter-bomber within the Rebel concept of operations, despite being designed long before some of the pilots were born *cough*Luke*cough*. There is no historical precedent of a fighter-bomber that served through all of WWII, and then through most of Vietnam. The closest analogy is the A-1 Skyraider, which was a favorite of pilots and grunts alike for many of the same reasons why the Y-Wing stuck around so long.
In the end, history should judge the Y-Wing against its Clone Wars contemporaries. From this perspective the Y-Wing’s design was so far ahead of its time, innovative, longevity, adaptable, and versatile that it allowed the starfighter to have a lengthy front-line career unlike any other in either the Star Wars Universe, or the real world.