Given the enormous lifetime of these devices, I’d say chances are pretty good! The only thing that’s going to make an M series Mac obsolete is when Apple stops releasing updates. If you can run Linux on it, that thing is going to last forever.

My concern is for the devices I have, which are usually newer, and for battery life. Linux doesn't even have full hardware support, much less efficient battery life on these now several year old devices.

Maybe things will unlock soon and stay that way long enough for it to be viable for me. I'm just not holding my breath.

Of course it's great to have a supported OS for retired hardware--regardless of battery performance. That's a different use case. And I salute all those who work to keep old devices out of landfills.