Steam and most of the content it delivers requires 32bit libraries to link into. Steam could build for 64bit, but it won’t help the gigantic amount of games that are 32bit also.
It would look a lot like steam on macos looks; so many games that technically should work, but have a little 🚫 next to them because macos bo longer ships with the 32bit libraries needed.







In the case of macos, it doesn’t even use proton. As for windows games on linux, I’m unsure of the exact specifics so I can’t argue them with you. The issue is any game with a linux build will require 32bit libraries to be available, and the community would have to do all of that support themselves.