I agree that TSMC is a
huge part of Apple and AMD's success. That being said, Nvidia has tapped Samsung and is on 8nm. I don't know how much of a difference the 1nm size difference makes but I assume that it would also increase costs for Nvidia. The cost difference would make their cards even more expensive and AMD would still be competitive.
As for Apple, again, yes, TSMC plays a huge roll in the success of Apple Silicon. However, Apple is not the only ones on 5nm. Qualcomm makes a competing ARM CPU, the Snapdragon 888, which is also on 5nm. But it still trails Apple Silicon in performance.
source:
https://www.androidauthority.com/snapdragon-888-vs-exynos-2100-vs-apple-a14-vs-kirin-9000-1191495/
Source:
https://www.anandtech.com/show/16325/qualcomm-discloses-snapdragon-888-benchmarks
So, yes, TSMC is very important to both Apple and AMD. However, the accomplishments of both Apple and AMD should not be discounted either.