The competitive online gaming community is not the gaming community.

I can play SF6 and Dota2 on Linux. Are those not competitive? If I'm able to play these games free of cheaters on Linux, what's stopping any other company from allowing me to play my games there? Guess what, games with kernel-level anti-cheat still have cheaters even when they universally block Linux from playing at all. Will allowing the OS with ~3% market share (specifically the subset of that 3% that will even be playing that game) make the cheater population skyrocket? I know your point is that you simply won't switch if you can't use/play what you want, but you're complaining about an instance where the only thing preventing you from doing that is the corporation who makes the product, and has nothing to do with Linux itself.

After the whole crowd strike debacle Microsoft is trying to remove most things from the kernel into user land, including anti-cheat. If this will actually makes wine possible for those games is still up for debate but either way kernel-level anti-cheat seems to be on the way out.

https://pureinfotech.com/microsoft-removes-antivirus-windows-kernel/

People are on Windows because of inertia.

If you look at just PC gaming, Steam charts show that the big competitive kernel-level AC titles are way down, the biggest one is the newest Rainbow 6, with 80k players of the 36 million people active on Steam right now, 10 million being in-game. Funny thing is, the biggest Steam title is indeed a competitive online shooter, CS2, but it runs fine on Linux.

If it was competitive gaming that was the only reason people aren't on Linux, most other segments would have seen a mass migration already. Competitive games can't explain why 95%+ of the community is not on Linux.