China may have only just begun to reap the benefits of its previous investments in aircraft carriers, but by the same token China has only just begun to incur the costs associated with aircraft carriers. R&D is cheap compared to production and especially operational costs.
I agree that carriers are useful, but the level of investment required to realise a credible capability is enormous, and the carrier itself is only a minor part. You need all the combat and support aircraft, many thousands of personnel both onboard and ashore, and a robust surface and subsurface escort capability and all their personnel. The cost required to realise a useful carrier capability is probably ten times the cost required to realise a useful nuclear submarine capability. In a benign strategic environment, that would be fine, for in the longer-term China can certainly support those costs. But when you are faced with the credible prospect of conflict against a superior adversary perhaps three or five or even ten years from now, finite resources need to be allocated where they can best serve to enhance the prospects of victory and avert the prospects of defeat. Ironically, the dream of a world-class carrier capability is likely to be fully realised only after the threat of war has already begun to diminish. In the long-term, China will be fine. The challenge is to get through the short- and medium-term. And I don't see how carriers, particularly nuclear-powered carriers, are going to help with that. To be clear, I am not suggesting that China should abandon its pursuit of aircraft carriers, rather that carriers should be de-prioritised in favour of capabilities that can deter potential adversaries more rapidly and cost-effectively over the period to 2035. Submarines, both conventional and nuclear, are at the top of that list.
So it sounds like you agree carriers are nice and important, but it's just that China cannot afford it. In that case, we have a huge disagreement. I'll make it simple to explain.
A few years back, when discussing future PLAN orbat at SDF, I made the argument that PLAN should benchmark USN because it's the world's most advanced navy and also PLAN's main potential adversary, and therefore target to achieve between 1/2 - 2/3 of the force of USN by the middle of 2030's. Given the "deteriorating strategic environment" in the last few years, let's say the target is 2/3 of the USN.
Chinese defense spending is about 1/3 of that of the US at nominal term, and should be roughly 1/2 in real term when taking into account the purchasing power and low cost. Chinese economy will likely surpass the US economy between 2025 and 2030, and will be anywhere between 1.5 - 2 times of the US economy by 2035, in nominal term.
China today has two conventional STOBAR carriers. In the most aggressive scenario, China will have built by 2035 four more conventional CATOBAR carriers (Type 003) and two nuclear-powered carriers, which will only start to construct in the 2030's. Effectively, that's less than 2/3 of the USN's nuclear-powered supercarrier fleet at 11-12.
In other words, from spending at half of the US's today to about the same as the US's in 2035 in real terms, are you saying China can not afford 2/3 of the USN by 2035? Keep in mind, China would still spend substantially less in percentage of GDP in this scenario than the US.
In your statement above, you almost make it sound like China doesn't know what it's getting itself into by jumping into the carrier building program, with all the escort fleet, combat and support aircraft, various personnel etc. etc. It's like they will have a sticker shock or something like it. I have to say this feels a bit condescending.
All the escort ships (055/052D/054A/054B) are in place and will continue to be built regardless how many carriers will be built given the "deteriorating strategic environment." All the aircraft are needed and will be built regardless how many carriers will be built: the difference being whether they're going to be parked on land (J-20/J-16/J-16D/KJ-500) without aircraft carriers or on aircraft carriers (J-35/J-15B/J-15D/KJ-600) to be forward deployed in the Western Pacific to give China more strategic defense space. And, for all the supposedly prioritized SSN/SSGN's, they are better off to go with CBG's in many cases.
Your suggestion really amounts to building some more SSN/SSGNs at the expense of a few large carriers. That's a false trade-off. A worse one.
To summarize, China can absolutely afford up to six large CATOBAR carriers and their associated escort fleet, support aircraft and personnels with defense spending as a percentage of GDP less than the US by 2035. And, a balanced force structure that include large carriers, SSN/SSGN/SSBN's and strategic stealth bombers are so much more effective and powerful than some narrowly-focused navy.