It's worth noting that TSMC is looking to exploit Apple's demand for the hottest silicon. The latest reports suggest that they'll cut the prices to lure in others, so Apple will be forced to ante-up or stay on an old process: https://www.techspot.com/news/97269-tsmc-may-cut-3nm-wafer-p...
It's fascinating to think about. If the Mac is currently a low-margin product, Apple might be forced to stay on one node until the better silicon becomes cheap enough to use in production. If Apple doesn't play their cards right, TSMC could shanghai Apple in the exact same way Intel got stranded in the sea of process enhancement.