Regarding your examples, OpenGL, SDL and OpenAL, they are all stone age technologies compared to what Windows offer in DirectX.
Wrong, you can use opengl to take advantage of advance features available on your graphic card. Such features are often inaccessible in current version of directx, but often accessible through opengl. OpenGL don't evolve much because it is already superior. You can't measure technological superiority by only counting the number of people that use it. I believe that directx is popular because game developer just make use of popular middleware that use directx. They typically don't write their own engine. Do you notice that everything is powered by unreal engine today?
SDL is a very fast library and is amazing when it comes to blitting 2d graphics
It also make it easier to use opengl. Hell, it even do audio stuff too. Just read the manual.
10 to the minus 6th power Movie = 1 Microfilm