I don't see how it helps Taiwan that much, but perhaps it makes it less attractive to China to take if TSMC can move.
Taiwan's semiconductor industry is literally not even a factor that plays into China's wish to reunify. It won't make a lick of difference.
https://stratechery.com/?s=intel
They were talking about this in 2013
Motorola GE Boeing
The list goes on…
also stratechery had few articles over the years
It's when there is a huge exit barrier that companies get away with all sorts of garbage.