These forums are always good for a laugh, so many insecure egos. No skin off my nose, I'm happy being one of the million Linux gamers currently on Steam. Once Steam OS leaves alpha & becomes the target Linux OS for developers to aim for game development on Linux will become more straight forward since it will eliminate any distro fragmentation. As long as your distro has the same dependencies installed as Steam OS you're good to go, not to mention that graphics driver support has exploded in the last few months and Unreal Engine 4, & Cry Engine were just released for Linux in preparation for Steam OS which will make porting to Linux MUCH easier. & just yesterday Codemasters pledged support.
Edit: The purpose of the Steam Machines is to give a Linux compatable set of hardware that will work well with Steam OS for people who don't have the time/knowledge to build a fully Linux compatable machine themselves. Valve doesn't care if you use their box, a third parties or build your own Steam Machine, or even if you use Ubuntu since all main Linux versions play Steam OS content & it's the content they want to sell.