>This makes Taiwan LESS strategic, not more, for US security, because now the US can build its own chips and isn't vulnerable to a Chinese invasion on Taiwan.

I think you're failing to take into account a number of things. First and foremost the very foundation of the US is based on respecting IP law given we're almost entirely an "information" society. If we suddenly steal TSMC's business secrets because it's convenient, what's preventing Europe and our allies from taking ours? Why would they respect IP law if we don't?

Second, regardless of the technical reliance we have on Taiwan, there's no planet on which the US wants China expanding and taking over other countries in Asia for political reasons.

The factories in the US ensure that the US keeps sending business to TSMC.