It's not only that. They have the knowhow, and a top-notch engineering team. The iPhone processor were developed over the course of 15 years and grew organically to become the M1. Even if you consider other mobile processors on par with Apple's (they are not) - it will take years before they can be adapted to PCs. And as latest Intel efforts show us processors that were not designed with efficiency as a key target from the beginning cannot be easily modified to challenge the M1 either.
Even without TSMC Apple has all the cards - experience in state of the art chips, phones, tablets and PCs, from the silicon to the software, all in one company. They should do some serious slipups before someone has even a chance to challenge them.
Don't discount the other engineering teams. AMD is currently not too far behind (even ahead in a couple benchmarks) despite being on TSMC's previous node. It's all gonna be pretty close.
I think there is good chance, they remain at the top, for a while, but a low chance there will be a huge gap to the competitors, when they have access to the same tech stack.
The M1's speed and efficiency are mostly not the result of something ground-breakingly smart, but 5nm TSMC and a non-modular design, integrated chip platform. In other words: They played monopoly and made a huge compromise on the design front. I don't expect they could pull off another leap like that soon. The M1 isn't magic, as far as I can tell.
There is good reason to believe that’s not the case. Oh having access to TSMC 5nm to other designs would definitely help reduce the gap, but we can see from like-for-like node implementations of previous A series chips and other ARM designs that Apple has a significant lead in architecture too. M1 has some really impressive new architectural features of its own that it’s hard to imagine their competitors being able to replicate any time soon.
According to AMD you get >1.25 performance at 1/2 the power usage when chips go from 7nm to 5nm. Some of that might be architecture but when x86 gets to 5nm the difference in performance might be fairly negligible.
