The "Chinese aggression" in SCS is just convenient jargon for domestic and foreign audiences that need to hear moral-sounding words to make themselves feel good. The real reason US is and will continue to have strong presence in Asia is, being a Pacific nation, it has core national interests in the region. It is also in China's interest to have strong US presence in the Indo-Pacific because the region would be more stable with US than without. Also, it's not in either China or US interests to have two blocks that are mutually exclusive and hostile to the other; better for China to compromise with US and negotiate co-leadership of the region, instead of playing with fire and try to push US out of the Western Paficic.
Generally agree, but remember that the USA is separated from Asia by the Pacific Ocean which is 8+ hours by airplane, 2weeks by boat, the time zone difference, culture/language etc. Most Americans have never even left the USA (and of those who do, the vast majority have only been to Europe).
NB. China is happy to negotiate co-leadership of Asia with the USA, as it is a huge step forward for Chinese influence, which would be risk free. It essentially means a G-2 where the US and China decides what happens in Asia, at the expense of Japan or India for example.
The problem is that the USA is not willing to cede sole leadership and treat China as a true equal. We see that with the attitude of US exceptionalism, the US Navy saying it will go wherever it pleases, that US should write trade rules for Asia etc etc