I won’t be surprised if Apple cares very little about that honestly.
They will move forward and on. They’ve never really cared too much about the compatibility part or capturing everyone and they will care less and less and less the bigger they get.
Workflows and tools will change and they want to lead there, not follow or live too far in the past.
Btw: I’m not saying I love all aspects of this, but it’s what I objectively expect.
I’ll give you my take on it (my education also meant I had to study RISC vs CISC processors, to even old Apple PowerPC CPU’s so I do find this area interesting).
Let’s assume for arguments sake you get more performance (this idea if 3x etc isn’t realistic, also you should look up the limitations of synthetic benchmarks which make iPad for example look more powerful than it is due to the architectural difference between the CPU’s).
If Apple went ARM next year, you’ll have a very Windows 10S experience. You’ll have to get apps which are on App Store, they may partner up with some vendors like Adobe or Microsoft to get their suite up. However, the idea of freely being able to download and use any software will be gone, as it is on Windows 10S.
For such limitations, it seems kind of pointless to have all that’s power - and then be limited in what you can do. Sounds like another one of their products right? The iPad
But I want to discuss a more pressing issue - for the majority of users, it is never the case we are starving for more power. Why go through the headache of moving to ARM for gains that you won’t perceive at the cost of a huge amount of issues?
I think we are far from an ARM MacOS/Windows which I believe would be actually worth switching to. Three years and Apple hasn’t managed to fix the keyboard, can they reall make ARM work in less than 5 years?
I don’t envy the developers working on that project, I’d run a mile!