TSMC's Arizona fabs (edit: need to qualify this with "today" and in the near future) are wholly inadequate to shift wafer volume out of Tawian if that were to ever happen. TSMC themselves have been candid about this - both the fact there is insufficient skilled labor and insufficient economics (materials supply chain, construction costs/process, subsidies, OPEX). If TSMC was serious about this they'd have invested heavily both in staff pipeline (university programs and hiring onramps), domestic executive function and supply chain - aside from taking subsidies and building tiny fabs that trail their Taiwan process nodes considerably, they've done little to diversify their fabs.