Nowadays Unreal Engine fill the role very well and can sit on top of any platform easily. Popularity wise , together with Unity have completely destroyed both Metal and OpenGL. Vulkan , stands no chance too. Unreal Engine is also open source and very easy to extend because of Blueprints. Unlike OpenGL , is not a C API trying to shoehorn itself into a C++ dominated world.
I have to use OpenGL 3.3 and I am amazed how badly designed it is. A brief look into Vulkan made even less sense.
I don’t agree with everything Apple does but killing Flash and OpenGL is two of my favorites. My only complain is that they have not done it as aggressively as they did with Flash. If they manage to kill JavaScript and HTML/CSS abominations I will become a hardcore Apple fan.