Ahhhh, makes sense. Also, after reading further, it appears I was wrong - TSMC has some operations in the US including some in Arizona - plus their interest in maintaining friendly terms with the US in order to preserve the existence of Taiwan is also an angle.
What still worries me is that ramp up time for fabs like these are on the scale of years - if we assume a fab started right now, we'll be making semiconductors in ~2 years at the earliest (very optimistic)? It seems like the root of the issue seems to be the inventory tax and accounting rules - perhaps an exception for the semiconductor industry would help rather than even a single domestic fab (which could be impacted by natural disasters as well).