Earlier quoted context omitted.
Yes but it's virtually the same core software stack as on the desktop. So the linux distros get a huge leg up in that arena.
Are you sure about that? Why wouldn't this be more similar to Android than, say, Linux Mint? Who says they're even using any of the typical userspace bits? I would bet a money (albeit a small amount) that, to a first approximation, they're really only using the Linux kernel.
Even if SteamOS uses different toolkits or packaging (which it very well might), the amount of effort to get those titles to run on typical desktop linux distros should be relatively very minimal.
I highly doubt it would be more similar to Android than Linux Mint simply because they have already invested time and money into making Steam run on the Linux Mint family of distros (i.e Ubuntu), and (to my knowledge) none working on the android stack.