With my PC, I could dual boot, as it's just reassuring that I can fire up my favorite games and they "just work" on whatever the latest Windows OS is I'm running, and the convenience factor is so much higher now that I'm running WSL2 and can do various Linux things, too. But cost-wise, well I've only ever paid for Windows when buying a pre-made system. When building, I've gotten various free versions of Windows over the years, like when I did a "Windows party" for the launch of 7, and they sent me a free copy of Ultimate (which was free to upgrade to 8->8.1->10. But obviously not available in general if you want a Windows license.)

And the cost of time... to fiddle with Linux and try to get all my Blizzard games working, maybe it's not as bad as it is in my head, but it seems like a hassle, and quite often, my spouse and my family members and my friends and I spontaneously want to jump into a game of StarCraft 2 or Valheim or Diablo 3, and I don't want anything causing me to stop what I'm doing and try to troubleshoot it for 2 hours while everyone else plays.

So, I run only Windows, and I put up with the once or twice a year that a new update comes out and potentially introduces some kind of notification or extra Start Menu tile, and I turn that thing off, and then I go on with my life without it. If I could have Linux with a "Windows gaming" channel like Netflix that always just worked for every game I play or will play in the future, I think I'd certainly consider switching to that. But for now, I'm not confident enough that everything I use my PC for would "just work" if I switched, with the same performance and lack of troubleshooting, so I do not do so.