I think you’re missing the point. It’s not about OS backwards compatibility, it’s user library backwards compatibility.
I never proposed to ax Proton, so I’m not the one here missing any points.
It’s also why they don’t need to incentivize native builds, because they already solved that problem on their own with Proton. Why put effort into having developers develop native builds when you could just put that effort into Proton and essentially get the same result (and extra benefits) without hoping the developers do something they didn’t want to do in the first place?
I explained several times already that game updates breaking Proton compatibility is a real thing that would not have happened with native games.
Game developers develop for dedicated platforms other than Windows all the time. They’re called game consoles. Native games don’t just mysteriously break on updates or suddenly ban players because the game developer out of the blue decided that Proton is cheating. First launch of games doesn’t annoy with those stupid Microsoft runtime installer scripts, etc. Proper native games could be optimized the way console games are instead of relying on multiple levels of Windows compatibility layers (the newest BS Proton has to deal with is gamepad compatibility for launchers via a special input wrapper) – they are just a smoother experience all around.