We also have to contemplate the possibility that Xi has calculated that the United States won't risk nuclear war to save Taiwan, even if doing so may be the only way to deter China from invading.
If I was president, I would hold a prime time address from the Oval Office to announce that any Chinese attempt to conquer or blockade Taiwan will be met with nuclear strikes on the Chinese mainland, including civilian targets. I would state my intent to sacrifice the lives of millions of Americans to protect Taiwan if that's what it takes. And to get the point across, I would detonate a nuke in atmosphere over an empty stretch of ocean between Guam and Hawaii, and release the footage for the world to see.
Yes, this would be insane.
But Xi's advisers may have determined that they can win a conventional war with the US over Taiwan, and that the People's Liberation Army Navy could keep the Strait of Malacca free from USN interference.
Xi may, correctly or not, have concluded that only such a threat could deter him. And that a US president is unlikely to issue such a threat.
We have to be prepared for the possibility that China will gain control over TSMC's foundries and use them to blackmail the West and any other unfriendly countries into submission.
If this is correct, then there are only three options: copy TSMC's capabilities in the West, destroy the foundries during a conflict, or deter China from invading. Or deny them a victory if they try.
But I don't want to hear "China wouldn't dare", "there's only a small window of opportunity where the weather allows an amphibious landing", "It would be the largest military operation in history", etc. China may have calculated that they can overcome any logistical hurdle. They're not stupid. They know all of this. But at some point, the hardliners will lose patience and demand results. And the hardliners happen to be in charge.