I’m sure TSMC would become untenable if either the US stopped buying or selling to them, though I tend to disagree and think that not licensing US tech would kill them faster. I’m pretty sure that much of that tech is not available from anywhere else and would just cause a full stop of their business, at least for some time. It’s easier to survive on lower revenue than it is on a fully shuttered assembly line.

There is likely a lot of US tech in that chip. TSMC is just a fab, they don’t have a lot of their own technology, they buy thousands of pieces of tech from all over the world to make their chips. A lot of that comes from the US.