Arch isn’t unstable. Users mess it up by installing a bunch of random crap from the AUR or fiddling with system files.
SteamOS addresses this by making the root level filesystem immutable and guiding the user to install containerized (flatpak) apps.
Using OSS in your product and giving the OSS devs resources to improve their software, instead of trying to take over their project? Did Valve not get the memo that big tech companies are supposed to be evil?? Oh right, they have a monopoly on video game distribution and all of their products rely on DRM.