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?

It also make it easier to use opengl. Hell, it even do audio stuff too. Just read the manual.