Everybody except Intel and Samsung is screwed if TSMC stops making chips.

Apple (and the rest of the mobile industry) would try to move to using Samsung's fabs and Intel would go back to being the undisputed king on desktops, laptops, and servers.

I think TSMC has like 2-3 times the fab capacity that Samsung does right now for modern chips, so there would be a huge chip shortage.

Apple's $200 billion cash pile would come in handy when trying to buy fab capacity from Samsung so they might come out ahead of less cash-rich competitors.

There would be a significant hit to processor performance. Samsung fabbed the recent Snapdragon 8 Gen 1, which has comparable single core performance to the iPhone 7's A10 fusion chip.