Earlier quoted context omitted.
Arch Linux is amazing. The biggest surprise for me was that it's more stable than so-called stable distros, probably because the various packages don't end up drifting several months from each other when keeping up to date. Hopefully this eventually results in more user friendly Arch Linux installers. The learning curve is an absolute wall when installing, even after several years on Linux, but after that it's pretty…
Ubuntu was likely too difficult for Valve to keep modified and up to date for their needs. Canonical doesn't have any reason to be friendly towards the specific features Valve needs to make SteamOS a thing, and Valve probably doesn't want to maintain their own fork of the entire Ubuntu distro. Not to mention, a default install of Arch is tiny and minimalist. It's the perfect base to apply your own packages on top of…
I wonder if they considered alpine? Though arch is a fine choice and makes me want one all the more!