So, the market is really rather less than that 1%...
The way to convince the mainstream vendors would be what's attracting them to release Linux support right now. The popularity of Linux devices for people who want to work on the same machines they run their servers on.
Like I said though, I'm not sure whether this idea is workable or even makes sense.
Linux needs to have similar certification. The rest would be to have customers look for it and prefer hardware that's certified.
https://certification.ubuntu.com/make/Lenovo
Or this:
https://support.lenovo.com/il/en/solutions/pd031426-linux-fo...
It's all really very nice, but even on certified machines, some hardware parts are not working on Linux (X1 fingerprint reader, for example).
But then I guess they aren't really doing their job when certifying things that don't work.