That's going to be something that's way in the future though. For the time being, manned fighters are much valuable than UCAVs. The main reason to go for the latter is because they're less expensive so they're a useful way to make up larger numbers. The equation for carriers is a bit difference because the most important variable is the limited storage space and sortie rates. Unless you can squeeze a lot more UCAVs into the same amount of space, or they can offer much higher sortie rates, you're generally going to want to have more manned fighters. As such, carriers with mostly unmanned fighters probably won't exist for another 20 years.
Also, this only counts for the fighter squadrons. All of the other aircraft, the EW planes, the AWACS planes, the S&R helicopters, and the ASW helicopters are all going to need be manned for the forseeable future. And even these only represent a small portion of the crew required to man carriers. It's just not something that can be rushed, and China simply isn't in a hurry to do so.
The USN simply can't move all 11 carriers to the Western Pacific. At any one time, only 3-4 are operational, with the others either in refit or in long term repair. The ones in refit can theoretically be rushed into service, but it'll take months before they're operational, so it's not going to happen until long after the start of hostilities. The US is unable to fight a long war so they'll probably never see action.
These waters aren't contested. There's no realistic scenario where the US is going to risk their CBGs in the China Seas, and they're likely to retreat behind the First Island Chain. Would having carriers be useful for China's strategy? Sure, but it's not that much of a difference maker.
Remember that the context is China's future naval aviation expansion. If we have 2 carriers currently under construction, then I think Chinese naval CCAs will be ready in about 5 years time, not 20 years.
Remember that we've already seen two 6th gen single-engine unmanned air dominance fighters during the parade 3 months ago.
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As for CCAs using up valuable slots on a carrier, that isn't actually a huge constraint for the Chinese military.
Sixth-gen single-engine UADFs operating from carriers will take the brunt of the losses from combat and can be used more aggressively against a force primarily composed of manned fighters.
So Chinese carriers have a larger number of UADFs, which clears the opponent's CCAs. Then you have Chinese UADFs against manned fighters, which should almost be an equal competition, but a UADF is like 3x cheaper. We can also expect somewhat more Chinese UADFs because they are physically smaller than manned fighters.
Your argument would make sense if manned fighters were significantly better than UADFs, but I do think they will be roughly equal .
But let's suppose manned fighters are significantly better than UADFs. Then yes, maximizing naval aviation capacity for a given deck space matters. But that only applies to the first (likely inclusive) engagements, because the manned fighters can't be replaced quickly, whereas UADFs can be quickly replaced.
And for operations to the Second Island Chain, it's a maximum of 3 hours flight time for UADFs to fly to a Chinese carrier, and bring it to a full airwing.
In addition, given the distances involved, we could have additional CCAs/UADFs launched from land bases. The Type-076 is also suited to launching CCAs/UADFs. We also see the $1 million containership being tested with an EM catapult to launch low-end CCAs.
So overall, maximising carrier slots is far less important for the Chinese Navy