Because it still doesn't fully support all of the hardware on M1. I know it because I used Asahi while I had M1. Now I have M4 for work and it doesn't support Asahi at all.

I just use Linux PC as much as possible instead. And that 4$ M4 is just a fancy presentation computer I use when I travel.

Personally I would spend thousands on an actually great Linux laptop, but there are still none around.