We don't even need native games. Proton, when it works, is amazing. Win32 is effectively now the stable ABI that Linux always needed but never had.
The real problem is kernel level anti-cheat, which will never happen on Linux, but more importantly, gamers should be pushing back against it even on Windows. It's invasive. The latest of which you can't even enable virtualization support in Windows if you want the anti-cheat to run, which also means you lose virtualization based security, no WSL, etc. It's completely obnoxious and I hope Microsoft cracks down on it, because if they do then more games will run on Proton.
I hope they don't. Competitive gaming has been begging to stop cheaters for a long time. Ring 0 anti cheat has shown to be very effective against the vast majority of cheaters. Compare CSGO with something like Valorant. It's clear it's effective. Is it invasive? Sure. Is it mandatory? No (sorry you just cant play the game).
Bring back private lobbies/private servers then. Make the anti-cheat optional. Those that want to play in public lobbies have to rootkit their PC or play on console, those that don't still get to play the game without it but not in public lobbies.
The main issue is that a lot of people I know need things like Photoshop or propriety CAD apps or video editing software where the alternatives are simply not acceptable - sure I can mention some OSS alternatives but it's not really my field; this is their job and they can't really take the velocity hit, or waste time finding out mid-project that it can't do what they need it to do.
Games requiring anti-cheat however are a big issue that still require a dual boot Windows or VM.
I realized recently that at some point I stopped even checking ProtonDB before buying games on Steam, I guess because its been so long since I've run into one that didn't work. I play a pretty wide variety of games, but not so much the type of competitive multiplayer FPS that seems to have the worst Linux compatibility due to anti-cheat.
Many ultra-popular games don't work due to anticheat, but some do. Dota 2, Counter-strike, Marvel Rivals, Overwatch 2, among others work perfectly fine. We've also reached a point where virtually every offline game will work too.