The M-chips are insanely powerful. So powerful for my regular use that I'm still on M1-generated devices and don't really need to update. Perhaps in a few years when both local-running LLMs are good enough on regular consumer hardware there'll be a good reason to upgrade.
As a disclaimer though, I haven't even tried to really run local models on the M1 as I also have a 'gaming PC' that can run them fine.
I feel much the same. I feel like the next time I upgrade I could splurge a bit more and get a really bigger CPU and storage to be even more productive with.
However the main reason I would upgrade is to run LLMs locally and RAM prices are making this a no-go. One day if RAM comes down to earth I'll upgrade. If not I'll stick to this old machine for a long time.