and the vast majority of Linux Devs will just continue building what they were building before, and still complain how windows users dont migrate to Linux (cough usability cough)
If linux came preinstalled by default and vendor supported, regular people would use linux as well. Usability is actually pretty good these days, arguably higher than Windows since you don’t have to deal with this BS.
Yes, you can buy Dell laptops with Ubuntu preinstalled and supported, maybe Lenovos, not sure, but it's not the default, available only on custom builds online and on business (expensive) laptops, so most regular people don't bother.
Edit: well, there's the SteamDeck as an example of mainstream vendor supported system with linux, I guess. Some people go through the trouble of installing Windows on it, but most people don't bother and stick to what it came with.