I googled and this is what Valve says:Don't really know how Steam works but pretty sure most, if not all of the primary distros will work...... they have the same kernel.We have that with Windows, too. Steam, like Origin, is not a good copy protection. Like in the old days, you copy and paste the crack and you can run the game - and that portable.The issue with game producers and Linux is the open source platform, the computer game industry wants to protect it's product, for obvious reasons. The Linux fanatics want everything on Linux to be open source and will crack the games and make them freely available if they can.
Steam for Linux is already available so it's a viable workaround for Linux users and as Linux becomes ever more increasingly user friendly more average consumers will start using it and the fanatics will ultimately become the minority.
Linux has to many distributions, can you run Steam and the games offered by this version on any distribution? I don´t think so. In my opinion, it´s good that the PC has a universal platform (Windows). Otherwise we probably would need several devices and operating systems to get the functionality of the PC we have now.
"Currently, Steam for Linux is only supported on Ubuntu 12.04 LTS or 12.10 with the Unity, Gnome, or KDE desktop. Additional distributions will be examined for support as time permits. For more information on Steam for Linux, see https://wiki.ubuntu.com/Valve. If you are running another distrubiton of Linux we will be unable to offer support as these are not officially supported. If you are having trouble running Steam for Linux on another distribution we recommend switching to Ubuntu 12.04 LTS or 12.10 with the Unity, Gnome, or KDE desktop."
https://support.steampowered.com/kb_article.php?ref=1504-QHXN-8366