> TSMC is dominant in technology AND volume. It chip shortage would be massive. Redesigning everything that has a TSMC chip in it to use something else would be a massive undertaking.

That's true and yet I'd say that's not my problem? The market will be fine. If anything that means more software work for me. New opportunities will arise. People won't buy a new phone every year for a while (which is objectively a good thing!). The M series MacBooks are so good now there's virtually no reason to upgrade to M2 or M3 if you have the M1 (like in my case). I fully expect to use this computer for the next decade. My desktop PC is basically unchanged since I built it in 2016 (+1 extra SSD I've added after, but that was it). The i7-6700K in there is still chugging happily along.

Apple have more than $100 billion of cash at hand. They will be fine no matter what happens. It's not like they didn't change chips before :)