steamOS coming out for PC.

This is unfortunately unlikely. Valve controls the hardware of the Steam Deck, which in all of its variants is functionally the same platform with the same hardware in it, versus the near-inifite number of hardware combinations any random user could have in their PC. This means they can tailor it specifically to work perfectly with the platform it runs on. It won't work that way on J. Random Gamer's PC. The hardware support would be a nightmare and require a ridiculous amount of manpower to maintain.

Remember that hardware support is already the major weakness of Linux in all of its guises, and this is true even for massive distributions like Fedora, Debian, and Ubuntu with tons of people working on them. Drink every time you're scrolling one of these threads and someone says something to the effect of, "I would use Linux on desktop if my [ wifi / video card / printer / sleep and suspend / Bluetooth / VR headset / etc. ] would actually work right."

I'd doubt Valve would be willing to kick that beehive just for the karma points, or whatever. That's not to say that enterprising hackers have not already figured out how to install SteamOS on devices it's not meant to run on, but that doesn't mean it'll work right with all (or most) of them.