So, I don’t know what information this is based on, but I’m questioning it.

High end gaming rigs come in pre built, for people who want that kind of warranty, or, more often in my experience, the people who own them build them. Which means they’re not super fussed about installing a different OS.

It’s more likely that some subset of them play games that require windows (VR, some racing sims, competitive online games that require kernel level anti-cheat etc), and won’t switch because of that.

There may be some subset of the gaming populace who wants that without the fuss, and usually they buy consoles. Computer gaming is what it is because people very often like control.

I’m a tinkerer at heart, and one of my older brothers used to build custom gaming rigs as part of his business back in the early 2000’s. Most of my family and quite a few of my friends have been computer gamers for decades.

I’d be willing to wager that a fair number of computer gamers aren’t bothered about the installation process of steam OS, but might be wary of limiting the games they can play using it.