I suggest you read Sun Tzu’s The Art Of War as well as the History of the Roman Empire.

This isn’t about China or the US specifically, it’s simply a mix of strategical thinking (nullifying an adversary’s main advantage makes victory far more likely) and how nations at the specific stage of a nation’s growth that the US and China are at spend money in their military - China is a large nation climbing towards Empire stage so their resources are increasing but they’ll still parsimonious in their use (because that’s exactly how nations climb up from poverty) hence it makes sense that as they have more resources to increase their military might they’ll put a lot of them in things that give them the most bang for the buck (and that includes countering their main adversary’s most relied-upon military strategy after the Vietnam war - the Carrier Group), whilst the US is at the late stage of Empire and already in decay, which means a fat, glutonous system of power used to lots and lots of wealth floating around and prone to grandiose projects both for the seeming prestige and because they’re massive patronage operations and opportunities for corruption and taking a slice of the money sloshing around, and said waste in their military is allowed to happen because, due to their past successes and their size, they trully believe they’re unbeatable.

This shit happens again and again in History - it’s not even the exception, it’s the rule: great empires get killed by the very elites in them becoming ever worse parasites and overconfidence in their might.

Things like the rise of a “Make America Great Again” movement spearheaded by a populist who himself is the ultimate rentier parasite is actually a pretty typical phenomenon of such a phase - again just go read the History of the Roman Empire.