There is already something like that and it's called "consoles". Also, steam comes with a lot of bloatware and some things that you could easily call spyware as well.

If you want the most of your hardware, I suggest installing arch linux without gui and only running games via gamescope (for example).

引用自 SomeMMORPGplayer：

steam OS that would replace windows and linux

Are you aware that SteamOS is a Linux operating system? Sure you can replace another variant of Linux in your computer with it but you'd still be running a Linux operating system. Also even if nothing else is installed on SteamOS, Steam client, integral part of SteamOS, will gather telemetry from your computer.

Linux is great for old computers but Newly store bought computers dont work on Linux. Its the kernel that has all the drivers. thats why windows is king.

I was hoping for that too when I considered replacing Windows, but so far, reviews show that it's terrible for PCs at the moment.
Hopefully, Valve will improve their OS for PCs in the future

引用自 Numlock687：

Linux is great for old computers but Newly store bought computers dont work on Linux. Its the kernel that has all the drivers. thats why windows is king.

That's a false narrative. There are some hardware issues, but I have yet to find a laptop that I couldn't wipe clean of Windows and install Linux.

引用自 𝔇𝔬𝔬𝔪𝔤𝔲𝔶：

I was hoping for that too when I considered replacing Windows, but so far, reviews show that it's terrible for PCs at the moment.
Hopefully, Valve will improve their OS for PCs in the future

SteamOS is more of a specialized Linux distro designed with the Deck in mind. It's not a whole new OS.

引用自 SomeMMORPGplayer：

it would be a great idea in itself to havea steam os that would be designed specifically to play video games and browse the web. No bloatware, no spyware, no spying tool. just raw unfitlered gaming and full access to the entirety of our computer( minus the os space needed)

You could install a stripped down Linux distro, install Steam on it, and run it with Big Picture Mode. That's basically SteamOS. SteamOS has specialed tweaks for the Deck hardware, but the underlying OS is still Linux.