He's talked about his game before: http://timothylottes.blogspot.com/20...hy-gl-now.html
If this happens, and I like the GPU, I'm definitely building for this platform! As someone developing a game on Linux first and later porting back to Windows, I can say first hand that Linux is an awesome platform for games, here are some of the highlights for me,
(1.) Low latency direct access to input via /dev/input/event*.
(2.) Nothing running in the background, game gets the full machine.
(3.) Awesome GL drivers on NVIDIA at least (and no Windows WDDM latency).
As someone who is not enslaved to Visual Studio or the complexity nightmare of a massive C++ based project or engine, I've got 1 second compile times on Linux with gcc and optimization on with my C based engine. This is part way possible because my engine uses no headers, because in Linux, it was trivial to just write my own headers in my source for any external interface I needed (all of which are provided by simple Linux system calls, with the exception of OpenGL). My development iteration time on Linux is as fast as a key stroke to save my source in the text editor, which automatically triggers a background compile, and instant in-game reload of a shared library binary without exiting the game. I don't use an IDE or any debugger, it is just too fast to simply modify the code while it is running to try stuff and print stuff on the screen if necessary.
He wrote that in November. Funny, that the SteamBox is going to be something like that. I wonder if he had been in talks with Valve. Or if he's going to be now :P
I'm using GL instead of DX for my game (personal independent project), and here is why.
I'm not supporting MacOSX, but I'm planning on supporting a bootable "Steam Stick" USB2/USB3 thumb drive Linux image which runs Steam and can enable MacOSX users to run the game on their hardware.
DX11.1 situation is now the same thing. DX11.1 limits important updates like UAV's in every pipeline stage, and constant buffers as regions of other buffers. Things which can easily be done in GL on DX11 cards (don't need DX11.1). This move will limit what game developers can do, and it will negatively impact engine tech. My game for instance requires the features I just mentioned. To put it bluntly, when I'm finished, it will be obvious what you are gaining in visual quality, and gameplay, when a developer goes nuts and pushes a modern PC GPU to the limit as enabled by an API like GL4.3 which exposes what the hardware can do.