And what grounds do you have for your suggestion that the US has several folds more munitions than China and has an military industrial output that easily surpass China? When even western think tanks don’t agree either your opinion either.
The US has a military that rivals the PLA in size several times over and thus should have several times more advanced munitions.
The US doesn't need a military industrial output that surpasses China for China to lose a war of attrition. The way geography works, China cannot really damage America's industrial centers, but the US could over time, attrit Chinese industrial centers. To prevent this from happening, China must be prepared (and thus sufficiently armed) to destroy the entirety of all US aligned forces and their supporting infrastructure in the Western Pacific along with the rest of US forces when they inevitably are brought to bear against China.
The PLA will need to at least equal the size of the US military, if not be larger than it in order to properly wage a prolonged war of attrition against the US where the US brings its entire military might to bear against the PLA.
In such a war, we should expect to see the US kicked out past the 2nd island chain in a PLA opening strike. But the US has forces and bases in Australia, Alaska and Hawaii that would be untouched and thus be capable of supporting future missions to slowly regain air superiority within the Western pacific. Hypothetically, that might look like having 2 or 3 CSGs regain air superiority over Hokkaido, and then repairing Chitose Air base and spinning up another airbases from other airports on Hokkaido and using Hokkaido as a stepping stone to regain air superiority over the rest of Japan and then using that to degrade Chinese industrial centers.
Thus it is crucial that China have the magazine depth to destroy whatever mass of USN assets that shows up. In a worst case scenario that would be every CSG plus the French and British carrier groups, where every escort is outfitted with a missile defense focused loadout. So you need enough missiles to match that, and more to spare.
The most important point is that the PLA needs to have the firepower for the worst case scenario. Stakes are so high for China in any US-China war, that victory has to be guaranteed regardless of what the US will bring to bear.
