Well, outbidding everyone else seems to have worked up to a point, hasn't it. Of course, we could say that we're living in unprecedented times with regards to the demands currently being placed on fabs, but I'd say that I would've been worrying about TSMC being a fragile bottleneck for more than one reason, and for more than a few years now.

Also, I'm not exactly sure we should be claiming what is and what isn't realistic for a trillion-dollar company. People could (and probably did) argue that they had no hope of catching up to Intel/AMD, and yet here we are, with Apple arguably having surpassed both, at least from an energy efficiency point of view.

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.