SteamOS development was only contracted-out by Valve and while many like the notion of it, SteamOS is barely different than building a Linux machine and setting Big Picture Mode to execute on startup.
Really? I thought it was developed in-house. From what I understand much of their company was focused around Linux at the time (Steam, SteamOS, Hardware, Source engine port, L4D2, etc...).
I'm sure they also have/had contractors working on it like they do for the other Linux gaming effors but a claim that it was "was only contracted-out by Valve" needs something to back it up.