Taiwans rule. Foreign tsmc fabs have to be a gen behind. This would definitely change if China took over Taiwan, but who knows what China will do or allow at that point. They could shut the whole US fab down if they want. Even if they did try to re-tool the US fab (taiwan or china or tsmc) in a few years, it would cost billions and a lot of time to get it done.
How/why is that blocked?
Would it still be if China invades Taiwan?
Taiwans rule. Foreign tsmc fabs have to be a gen behind. This would definitely change if China took over Taiwan, but who knows what China will do or allow at that point. They could shut the whole US fab down if they want. Even if they did try to re-tool the US fab (taiwan or china or tsmc) in a few years, it would cost billions and a lot of time to get it done.
Taiwan is incentivized to keep the latest and greatest local, so they can hopefully get protection from the USA and Europe