Vulkan successor to OpenGL?
If I read between the lines it looks as if Vulkan could be a successor to OpenGL (i.e. Vulkan being rebranded as OpenGL 5.0 at some point) because it would allow much of the cruft that has gathered in OpenGL do stay behind in OpenGL 4.0.
Obviously they wouldn't openly acknowledge that at this stage so they don't alienate developers but I don't see why this couldn't happen in about two years. Especially if Vulkan proves to be a success.