What a gross trivialization of the chip design process. If all a company had to do was get first in line for TSMC's process, Intel would drop all their fabs and just pay that money to TSMC to beat AMD.
What money? They already paid them. Building fabs has a massive upfront cost that you depreciate for decades. The economics have to make sense for them to move to TSMC
Apple has good designs, consistent long-term plans, and doesn't have to directly compete with Intel over domination in the x86 market. They offer a complete package outside the x86 market. This fits well with who a market leader like TSMC would want as a partner.
For TSMC, it would be an error to start large-scale production of chips for someone that still has their own manufacturing capability. TSMC would have to allocate less fab capacity to their existing customers, and those won't like that.