The irony is that for most of the tech industry TSMC is unavailable. Nvidia, Apple and AMD have booked all the manufacturing slots for the foreseeable future. It's been this way since 2020.
Yes, their loss would have a huge effect, but many are having to cope with that situation today.
I suspect they'd be in much worse shape if Taiwan were invaded.
First, they'd find themselves competing with current TSMC customers for the non-TSMC foundries.
And second, an invasion of Taiwan could lead to a full out war with China, which might mean the non-Taiwanese fabs have their production priorities overridden by the warring governments.
What would be the casus belli?
Quite literally no country of even remote significance on the world stage (aside from the Holy See) officially recognizes Taiwan.[1] By what pretext would a country declare war against China as concerns Taiwan?
[1]: https://en.wikipedia.org/wiki/Foreign_relations_of_Taiwan#Ty...
I'm not remotely qualified to predict that. Perhaps I shouldn't have mentioned it.
Should China decide to strike that supply chain--whether by accident or on purpose--the result would be US military casualties, and that would have a strong likelihood of precipitating outright war.
Multiple US companies with trillion-dollar market caps that are completely or near-completely dependent on TSMC.
Remember that Japan attacked the US in WWII largely because we cut off their oil supply. Now, let's watch China cut off the US's supply of advanced semiconductors, and see how that goes for them. You bring the popcorn, I'll bring the beer.