This might well change if China takes back Taiwan. If that happens, China could engineer a situation where it's better for the local powers to cozy up to China, than to take the side of the distant US. Even though the US, as a distant hegemon, is the better option, the US might not have the power to keep China at bay any more, so the lesser of the two evils for everyone could be seen to give in.
If I were in the Defense Department, I would be creating SOSUS-like arrays near Taiwan, Japan, Korea, and the Philippines, plus an R&D program to create a swarm of super quiet autonomous midget submarines to go along with it. Basically, take unprecedented steps to make it tremendously dangerous to invade Taiwan, even if China has air superiority. (I very much doubt we'd be able to prevent China from getting that in the long term, even temporarily.)