Even gamers nexus' Steve today said that they're about to start doing Linux games performance testing soon. It's happening, y'all, the year of the Linux desktop is upon us. ᕕ(ᐛ)ᕗ
Edit: just wanted to clarify that Steve from GN didn't precisely say they're starting to test soon, he said they will start WHEN the steam OS releases and is adopted. Sorry about that.
If I recall correctly, this has never happened the way it's happening now. It was a matter of "hey, you can fork it on GitHub and make your own iso thing", hence why there was a "holoiso" or something like that that (I keep forgetting the name) where people used if they wanted to install steamOS on a device. This one is straight supported by valve. Like "hey, here is our official steam OS that we use on our steam deck. Use it and we will support you".
Iirc the original steamOS was Debian based and you really had to be an experienced Linux user to use and enjoy it.
With the new steamOS (arch based?) it's a much more streamlined experience and opens up the user base because of it