And we don't even know if US jets are 5th gen. What recent official US documentation that dismiss J20 as not 5th gen (except PLA old classification system that -1 gen across board). Using 5th gen as aggressor to simulate 5th BECAUSE 5th gen isn't about kinematics (i.e. F16) - it's about sensors and other capabilities, why 4th gen gets stomped by 5th gen chillaxing from BVR. Why F35 fine with being more sluggish multirole vs F16.

It's well known PRC turbojet is not at parity with US, but it's also competitive - i.e. not many generations behind, and by all credible accounts have surpassed RU in recent years. The point is they went from having to import engines to having entire supply chain to build 100s of cores at scale, FULLY DOMESTICALLY within last 10 years. That's not just fruits, that's an orchard in terms of statusquo disruption.

>F35Bs

I don't think PLA wouldn't make SVTOL with gimped range if they could, because SVTOL trade for range morely optimized for IndoPac/PRC backyard. SVTOL was good compromise for marines wanting to keep VTOL and select F35 partners with amphib size carriers when program was conceived 30+ years ago, when range/operations was designed around NATO conflict where SVTOL was strategic using makeshift and RU was just across the horizon. That's made increasingly irrelevant now that longer range strikes are proliferating to the point where liability of gimped range means launch platforms (amphibs) can't even operate close enough to launch, which is extra but kick when gimping Bs also gimped A, Cs.

> competition to America's air superiority

The credible competition is the entire PLA concentrated in theatre to prevent US from establishing air superiority in the first place, so in that sense NGAD can take as long as needed because there likely isn't an NGAD CONAP that works againsts PLA, hence the program reset. I would say there isn't a credible way for US to establish/sustain air superiority because superior US aviation can't be sustained. But you're right about attrition, PRC fine with losing entire PLAN if it means US loses entire USN, since PRC has 300x+ ship building capacity to reconsitute faster post war, and global security architecture breaks when USN gone.

> they know that China's 5th gen jets struggle to maintain 4th generation

Again which reports suggest US/DoD thinks PRC struggle with 5th gen operating as 4th gen. What's being written suggest they know the opposite. Excessive amount of words reports have been written on PLA aviation in last 5 years... the opposite of "rightly ignored"... it's borderline fixation. I uppose to mass production of F35s is tacit admission that US is going to lose F35s. Or USAF regrets deprecating all the tooling for F22s when they realized need to for more 5th gen airframes.

>limiting their aircraft inventory

J20 for F22, J35 fo F35 in high/low 5th gen mix. So they are, in fact replicating US high/low mix. J20 production is only 100 / year, about F35 production. The parsimonious interpretation - maturing Chinese aerospace is at point to match US in production, they want 2500+ 5th gen fleet just like US. Short/medium term they're just trying to close the 200 vs 600 5th gen airframe gap. If anything it's tacit admission they're comfortable enough with their 5th gen efforts to mass produce. Or that procurement wise, US seems to be the one who is NOT certain of their 5th gen, holding on to F18s, and now F15EX to plug the low mix gap, while figuring out how to modernize high mix with NGAD.