Linux is a bleeding edge operating system. it bleeds so much that its get outdated in 6 month flat. the development pace is huge. even then when it comes to hardware feature support, especially in GPU department, it SUCKS.
before i continue this discussion let me introduce you to a very advance game project. Xreal, the only application designed to utilize opengl 3.0 and above. yes that is correct, right now i can only find this application that actually uses ogl 3.0. more irony about is that there no open sorce Ogl 3.0 driver support till date. only closed source nvidia driver sport new specification and somewhat also by AMD/ATI.
anyway xreal is a heavily modified ... and i mean heavily modified quake engine that can real multiple files like from doom and unreal 3. sadly this project is another one of those 1st person frag game. there just too many death-match kinda games which are very advance. i would have love to see some good story based games with super graphics.
coming to opengl part, although we have the specification, implementation is taking time. and the story doesnt end there, khronos group which is responsible for laying the specification for opengl have been slow, uncommunicative abd quite stubborn. they have somewhat refrained from taking radical steps, on the other hand Microsoft had gone h\ahead with radical directx10 and now directx11. that means we have a capable hardware only opengl specification are missing. thats a shame. opengl was once the pinnacle of graphics APi, was much like and industry standard, and now it is just biting dust. tch