It works pretty nicely on linux, you have "mobile" environments like phosh, KDE mobile and that are pretty seamless between handheld and docked "desktop" usage. They have support in app toolkits like gtk and qt for applications that change based on screen size to accommodate mobile users. It's pretty nice: https://tuxphones.com/convergent-linux-phone-apps/

The reason why it didn't work for microsoft is because adobe, valve, and aren't going to whatever framework just because microsoft wants them to. But in the linux world you can just fork and fix. Even apple has a lot of leverage to force developers to act in a certain way if they want that app store $$$.

Obviously the hardware isn't all there yet in the open source world (the pinephones are pretty underpowered), but in terms of software all of the right stuff is there. And don't tell me the UX is too complicated for new users. Gnome's design is literally a ripoff of MacOS and KDE's interface is pretty much Windows.