Millions of gamers on Linux and Mac (with growing numbers) tend to disagree. It is a small number, sure, (less than 10%, probably somewhere around 5-7%) but large enough to be worth supporting.
Hell, there are even devs by now going “Linux first” and can live from that (even I wouldn’t go THAT far, though).
But you do you.
Meanwhile, I’m happily using my free OS, which is way faster, way more transparent and way more customizable than Windows, while still being able to play most Windows-only games and thanks to Steam Play even without needing to bother with Wine.
Of course, I dual-boot Windows for the few games not running on Linux - and because I’m a dev myself and need it for work.
In the end, everyone will use the system they are most productive with. But it should tell you something that of those who really tried out Linux or Mac, almost nobody goes back to Windows permanently…