I'd imagine that Valve is counting on others to fill that software void, as they frequently have in the past. Frankly? I can't blame them. Proton has gotten to the point where most Windows games "just work" on Linux the same day they release for PC. Death Stranding, Cyberpunk 2077 and Battlefield 5 all ran on Linux within a week of their release, and I'd imagine that compatibility will only get better as time goes on.