The phenomenon of everyone being blown away by the M1's performance is based so much on the fact that developers haven't built a lot of software on it yet.
Engineers all over the world will "figure out" how to take this fast hardware and make it feel slow again.
[1] - https://community.spotify.com/t5/Closed-Ideas/Revert-to-nati...
the spotify devs are quite capable, look at this ImGui port of the Spotify client: https://twitter.com/rogueops/status/1243269640815509504
Simply because most software people today is cross-platform, so most developers need to make sure their code is reasonably performant on x86.
As long as M2, M3, M4 keep getting better and maintain (or even increase) their performance margin over x86, then everyone running M chips will continue to see blazing performance.
The bigger worry here is actually if Apple somehow "figures out" how to make macOS feel slow again. I guess it depends on how "mature" you think macOS is at this point, if whole additional layers will inserted into the stack somehow.
However, the M1 is a huge leap forward. It gives you a maybe 3 year head start on all other computers.
So no, in a few years it won’t be as revolutionary and fast as it is today. But I think it’s safe to say you can expect an M1 to last you a good few years longer than a similarly priced Intel based laptop you can purchase today.
I think there are now more tools to help with phenomenon. For example for web dev, chrome has a built-in cpu/network throttler so you can simulate a low-end device.