1/3. Cost of Su-35 is inflated for China because it comes with parts and support, i.e, as long as the Sino-Russian border is open the logistics just depends on trained PLAAF personnel.
2. The Su-57 is not intrinsically a problematic type to produce, given that it's, designwise, more or less a modified Su-35. The problem is money; the Russians can't finance the full-scale replacement of their Flankers and MiGs because of the damage done to the Russian economy.
4. Do we need to source the TV show again? It's around 800 million RMB. If you look at publicized costs of J-10As, the Chinese don't seem to enjoy a cost advantage in aerospace.
6. Except the counterpoint is that it's already compatible with Russian systems. The R-37M, for instance, is a very promising Russian missile. The Su-57 fundamentally lacks the same bay length issues that plague the J-20. Adding a second inventory of Russian munitions to PLAAF equipment reduces the chances of China simply having weapons EW-countered or lacking key capabilities. Missiles are currently a key weakness of the PLAAF, while the PL-15 is excellent, it's likely outranged by the AIM-260. Comparable Russian air-to-air missiles can reach 290 km range.
7. This is assuming again that the Su-57 sucks. You're looking at yet another long-ranged heavy air superiority fighter, but for a mediumweight price.
8. You're strawmanning. I'm not implying the J-20 is a failed system, I'm saying purchasing the Su-57 has nothing to do with it failing.
9. There are rumors extant that the Chinese will get a "6th" gen up by 2025. If such rumors are credible, the easiest way to do so is simply to upgrade the J-20.
10. Which doesn't preclude purchasing Su-57s, given that China will require time to get its production up to speed. Russia provides a second production source that alleviates pressure on the Chinese MIC. Russian Su-57 fixed costs (factory, suppliers etc) can be allayed by the usual Russian export market; i.e, Russian production doesn't have to cover China alone and "neutral" countries aiming to buy Russian to avoid purchasing American for 5th gen cover the rest of fixed costs on Chinese purchases.
1/3. Now you're suggesting China make a large scale purchase of Su-57s without having the infrastructure, personnel and maintenance capabilities in the country to operate a fleet of Su-57s? You're digging a deeper hole for yourself for why such a purchase doesn't make sense.
2. I never said that the Su-57 is problematic to produce, I'm saying that between now and into the foreseeable future, by the time Russia's Su-57 orders have been fulfilled and are able to fulfill any hypothetical PLA Su-57 orders, whatever the costs are of J-20 and/or J-XY/J-35 would have also further reduced, making it dubious as to whether Su-57 will even be cost competitive to J-20s and/or J-XY/J-35 (assuming it even was in the first place, even looking at procurement alone).
4. Without clear cut cost breakdowns of equivalent aircraft and everything that goes with them, the numbers mean little to nothing, especially if it is for an aircraft that is only at the beginning of a potentially long production run.. So I definitively reject your notion that we know what the true equivalent costs of the aforementioned aircraft are next to each other.
6. This is a deflection. Regardless of whether Su-57 is compatible with Russian systems or not -- and this is assuming the PLAAF is even interested in Russian systems to begin with -- the Su-57 most definitely is not compatible with PLA systems and other aircraft and platforms and would require significant additional investment and work and time to enable that. By the way, the R-37M most definitely is not the equivalent of PL-15; the equivalent of PL-15 is K-77M, whose range most definitely is not 290km. Considering PL-15 is now a decade old from when it first began test fires and going on half a decade old in service, the PLA are obviously working
7. Whoever said the Su-57 sucks? The Su-57 is probably a perfectly good aircraft, but introducing it into the PLA in relation to other opportunity cost platforms that they could potentially acquire, in context of fleet wide requirements for maintenance, support, and operations, and system of systems warfare, means procuring Su-57 doesn't make sense.
8. I'm not strawmanning anything -- you're the one who first said in post #220 "It'd get around "J-20" failure claims"". I'm asking you what "failure claims" you're referencing and why you think it is reasonable to speak about those claims as if they are widely held.
9. I'm not sure what rumours those are, please provide a credible source. The most reliable indicators I've found in regards to PLA 6th gen efforts suggest that they will enter service before 2035. I've not seen anything credible regarding 2025 for a 6th generation fighter to emerge.
10. What you're describing here is purchasing a limited number of Su-57s as a supplement for 5th generation fighters as the PLA spins up production rates of J-20 and J-XY/J-35. That is very different to suggesting that the PLA should buy Su-57s en masse as "low end" 5th gen complement to J-20. If the procurement rate of J-20s and J-XY/J-35 was deemed strategically unacceptable, it might be possible that a purchase of Su-35s to make up the shortfall might be necessary, but would hardly be desirable or ideal.
For yourself, and for the others reading, I'll put my points clearly.
The below points are all ones which you are either unable to refute with current information, and the below which are all the current null hypotheses which require significant burden of proof for you to change otherwise:
A - We have no evidence as to what the true equivalent procurement cost of Su-57 vs J-20 vs F-35 are. Therefore you do not have the evidence to suggest Su-57 is cheaper than J-20 to procure.
B - We have no evidence as to what the true operating cost of Su-57 vs J-20 vs F-35 is. Therefore you do not have any evidence to suggest Su-57 is cheaper to operate than J-20. If anything, common sense and other recent trends in force structure and O+M costs tells us that introducing a new aircraft requires substantial costs in relation to its O+M infrastructure.
C - We have no evidence to suggest that the PLA is interested in Russian subsystems (weapons or sensors) that Su-57 may be compatible with. If anything, current and prior evidence in recent history overwhelmingly tells us the PLA is interested in integrating its own subsystems into any imported aircraft if possible.
D - Current Russian production of Su-57s will be tied up until the late 2020s for Su-57s for their domestic use, and Chinese production of J-20s and likely soon J-XY/J-35s will only further steam ahead in this time, likely outstripping Su-57s in scale and affordability.
E - PLA procurement of 4+ gen fighters are likely to continue in the next few years at least, in the form of SAC Flankers and continued J-10Cs.
In context of the above, it is absolutely reasonable if not inevitable to say that yes, Su-57 is a capable fighter and offers a unique set of capabilities for a 5th generation fighter, but does not offer significantly more capable systems or characteristics given the above industry and system points, to reasonably argue that the PLA Su-57s should be procured as a "low end 5th generation fighter".
As for your "long" response, the point is, if the Russians can deliver Su-57s at functional costs similar to Su-35s (i.e, would be higher, but with spares and logistics included), it's worth buying in bulk because it's worth it. RMB-RUB exchange rate is almost at its post-sanction high, given Russia's poor response to COVID-19. Once again, the main argument for purchasing Su-57s is the price.
To put it another way, if the Russians offer to sell China Su-57s at 50 million USD a piece (which is still lower than that of the F-35), with parts and support coming in as part of a different package, would it be worthwhile to buy it? How about 20 million USD, just as a hypothetical? How low does the cost of the Su-57 have to be before it'd appear reasonable to you for China to make a bulk purchase of Su-57s?
I'm sure there are some hypothetical situations that may exist.
But in context of the current understanding of the above aforementioned null hypotheses, I don't see any reason why the PLA would be interested in purchasing Su-57s as a "low end 5th gen" force en masse.
Maybe the PLA will one day buy a dozen or two dozen Su-57s as DACT, and/or to throw Russia a geopolitical favour, and/or to see what the Russian MIC is cooking up at its leading edge.
Or, as I wrote above, if the procurement rate of J-20s and J-XY/J-35 was deemed strategically unacceptable, it might be possible that a purchase of Su-35s to make up the shortfall might be necessary, but would hardly be desirable or ideal. But we don't know what the PLA's aim for procuring 5th gen fighters is, nor do we know what the analysis of alternatives are if they are unable to procure J-20s and J-XY/J-35 to the rate they want -- i.e.: for all we know additional 4+ gens, and/or EW platforms +/- unmanned solutions might be more cost effective than procuring Su-57s.
So sure, there are hypothetical situations where it might be necessary or where it might make sense, but we don't have anything to suggest that is on the horizon or anything that suggests we can reasonable argue it is likely to happen at this stage.
Ultimately I'm not sure why you are so obsessed with the idea of the PLA purchasing Su-57s.
It's a fine fighter.
But it doesn't make sense for the PLA in the way you describe, with the information we have at present.