In an IGN interview, Valve's Pierre-Loup Griffais said that "[they] want [SteamOS] to be at the point where at some point you can install it on any PC". Below is a transcript of the interview. I tried to clean it up to my best ability.
Just like Steam Deck paved the way for Steam OS on a variety of third-party handhelds, we expect that Steam Machine will pave the way for Steam OS on a bunch of different machines in either similar form factors, different perf envelopes, different segments of the market, and get to a good outcome there. We definitely want to encourage people to try it out on their own hardware. We'll be working on expanding hardware support for the drivers and the base operating system. Just last week, we fixed something that was preventing us from booting on the very latest AMD CPU platforms. Last month, we added support for the Intel Lunar Lake platforms. We're constantly adding support and improving performance. We want it to be at the point where at some point you can install it on any PC, but there's still a ton of work to do there.
If the embedded video doesn't take you to the correct part of the video, the correct timestamp is 5:37.
EDIT: Here’s the written article of the video:
https://www.ign.com/articles/valves-next-gen-steam-machine-and-steam-controller-the-big-interview