OpenGL ES will need to be supported in some form for a long time to come because of WebGL, and perhaps existing Android and iOS games (depends how willing Google and Apple are to break backwards compatibility…). If not through native driver support, through ANGLE.
WebGL is a different beast from OpenGL ES, it doesn't require OpenGL ES's presence and can be implemented on top of any other 3D API that provides the necessary functionality (same with OpenGL and OpenGL ES of course).
FWIW i'd expect OpenGL on the desktop to exist for far longer than OpenGL ES on Android and iOS since the latter two do not put as much emphasis on backwards compatibility. Of course this wont stop others from implementing it, but that only helps when you have the source code and want to recompile an application - it wont help existing applications to keep working.
