It's been covered in the media that TSMC loans its employees to Apple. You can also tell that Apple's fingerprints are on TSMC's leading edge node processes because products using it clock lower and consume lower power than comparable Intel processes. Also, to my knowledge, TSMC doesn't particularly stand out in semiconductor sub-fields where Apple doesn't play, such as III-V, embedded memory, and photonics. They are definitely at risk of getting disrupted in these areas.
Apple is the biggest TSMC customer. I would be astonished if Apple doesn’t influence TSMC’s R&D, product focus etc.
But to characterise Apple as somehow abusing their relationship with TSMC as a result of what you’ve said is not right. It’s just a normal commercial relationship between a customer and a large supplier.
Also bear in mind that TSMC has a large number of mobile SoC customers - maybe they think that’s their strength and focus on that rather than say photonics. Seems to be working!
