That would be fine if the US and China were great friends and allies - like if it was the UK instead of China that was the semiconductor powerhouse. But things look stormy on the horizon. Even discounting a military conflict with China (not likely anytime soon, I think) an economic conflict seems very possible. As China begins to manufacture a larger share of semiconductors they could easily decide to favor their own internal industries that are customers of said semiconductors and not allow state-of-the-art chips to be sold outside (or to certain countries). We (the US) have done similar things in the past.

No. Dependence upon East Asian semi fabrication is a liability even if you're best buddies (as with Taiwan). TSMC was founded by Morris Chang -- hard to find a more reasonable, US-friendly, capitalist person in the industry -- but every time a butterfly flaps its wings in Asia-Pacific, we have to worry about the sanctity and continuity of our semiconductor supply chain.

NVDA just reported earnings and, while booming, it was not the blowout that you'd expect in the context of the greater demand picture for their products. That's in an environment where you don't have open multinational warfare in Asia-Pacific and their manufacturing partner TSMC is firing on almost all cylinders (water shortage excepted).

Fabs in the US and elsewhere in the Americas are more defensible in times of war, and more likely to prioritize demand from US companies when supply tightens.