This is true until you consider what that exact casual market looks like. Mainstream casual PC gamers are overwhelmingly concentrated in live service multiplayer AAA games with kernel level anticheat. Fortnite, League of Legends, Valorant, Call of Duty, Apex Legends, etc.
So it's kind of a hard spot where yes, 95% of casual windows gamers would in theory be much better off on Linux but the Catch-22 is the games that market is mostly concentrated on is the single category that still does not work on Linux.
It's not like Windows is an OS they love, it's just a mandatory anti-cheat wall, but its a wall Linux can't breach yet.