[1] Case in point: glibc's compatibility guarantees are weaker than what you get on Windows. (For instance, your system's glibc cannot be older than what a game is built against, which may present problems for devs using Fedora/Arch and players on Debian/LTS Ubuntu, something I've experienced first-hand for my apps.) The X11 to Wayland migration is also still underway. (Though things are getting better, the attitudes of some Wayland maintainers are a bit concerning: "I don't [care] what you think is normal behavior for games. You get certain guarantees with wayland. Deal with it. If clients decide to do exactly what they do on windows or X11 they won't work correctly." [3] I'm not sure game developers would enjoy such reception.)
[2] https://store.steampowered.com/hwsurvey
[3] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18...
Porting games from Android/NDK into GNU/Linux is relatively a child's play.
Playstation OS is also POSIX friendly.
Finally every serious middleware engine supports GNU/Linux.
Still the amount of studios that care about GNU/Linux is almost zero.
With Valve, there are no reasons to bother at all as a studio, target Windows/DirectX, let Valve do the work, collect the money with zero additional effort.
Now with Windows based handhelds, Valve will learn what happened to netbooks.
The comparison with OS/2 only applies at a very surface level - and isn't even the whole reason why OS/2 failed when it had to compete with Windows. Among other things:
1. OS/2 could only run 16bit Windows applications at a time when Windows was switching to 32bit. Even the 16bit Windows applications were not 100% compatible and that is despite using Microsoft's code.
2. OS/2 had much worse hardware support than Windows as everyone was targeting Windows. On the other hand IBM as a whole never put much effort towards OS/2.
3. OS/2 Windows support had applications either run inside an isolated environment or they looked "alien" next to OS/2 applications at a time when GUIs were still trying to look consistent. While this is also the case with Wine/Proton, the focus on games makes this point moot (and people do not seem to care as much about GUI consistency these days).
> Now with Windows based handhelds, Valve will learn what happened to netbooks.
So far every single Windows handheld review i've seen that compares it to Steam Deck mentions both how the UX is worse than Steam Deck and games are -ironically- more likely to have issues on the Windows-based one. The only two saving graces for Windows handhelds is that they tend to be faster (but only when running at full throttle which limits their battery lifetime - Steam Deck runs faster at lower watts for better battery lifetime) and that anticheat rootkits work on the Windows handhelds whereas they do not work on Steam.
And you also forget that Valve did try to get game developers target Linux and put a lot of effort in the ecosystem for literally years before making Proton, yet developers largely ignored that.
Microsoft is already half way there with WSL, as soon as they realised folks rather buy Apple gear for UNIX experience, instead of supporting Linux OEMs.
"Runs Windows better than Windows" didn't work last time, and won't now.
And if XBox really goes full speed ahead as cross platform brand, as the console rumor mill has been discussing, lets see how many Microsoft owned studios stuff keep landing on Steam.
It already works, i play games every day, pretty much all games i play are Windows games and i can count on my hands the number of times i booted on actual Windows the last three years.