First, I think it's reasonable to expect Apple Silicon Macs will receive 9-10 years of macOS support.This is exactly one of the main reasons that make some users uneasy. Once MacOS updates stop in 6 to 7 years time after device launch. Apple Silicon machines are pretty much useless just like piles of old mobile phones and tablets without software updates - too wasteful to throw away too little to continue for daily use.
After generations of users have seen and experienced benefits of MacOS on more or so open hardware, will be really interesting to see how once-again proprietary Macs play out in the longer term.
Second, when the time comes (10+ years) that OS support is a limiting factor, you could install Linux on them.
And it's not like deprecated Intel Macs easily support Windows 11 running on bare metal, so they're no different (i.e. just as 'useless') than Apple Silicon Macs in this regard.