Apple has alternatives to TSMC. Intel and Samsung both have comparable process nodes, albeit at a pretty high cost and relatively lower yield. Apple would prefer to avoid paying competitors like that, but in many cases they have no other option. The iPhone Duo display, for instance, is sold to Apple by Samsung at a considerable per-unit markup. It was that, or no folding phone.

Realistically speaking, "catch up to TSMC" is something that every single EUVL fab has failed to do despite tens of billions of dollars in investment. Spending money is the easy part, developing high-yield processes over a timetable of decades is the hard part. I think Nvidia and Apple both agree that paying TSMC to build American fabs is a smarter use of their money if they just want excess fab capacity.