Someone could write an OpenGL layer directly on Metal. There have been a few incomplete starts at that.
Meanwhile, writing an OpenGL-on-Vulkan layer has been a plan for deprecating/simplifying driver support for OpenGL for quite a while now. Might as well focus efforts on that.
Meanwhile, writing an OpenGL-on-Vulkan layer has been a plan for deprecating/simplifying driver support for OpenGL for quite a while now. Might as well focus efforts on that.