Sorry. Don't get me wrong.
Weird thinking open-source means "opengl only".
If there are two or three renderers: OpenGL, DirectX, software renderer, its fine. Like Irrlicht and Ogre, etc. did.
Whats wrong with latest DirectX version? its not decreasing performance, rather enchancing visuals.
Some compatibility issues, you know. We want make games playable by everyone.
With open-source someone can change it into opengl
I know but its a lot of work. Changing EVERY DirectX calls to OpenGL by yourself is too much.