What about Vulkan? They’d need to implement the same crummy APIs and semantics (that is a bunch of kernel and similar work) for an API that NVIDIA and AMD were

What about Vulkan? They’d need to implement the same crummy APIs and semantics (that is a bunch of kernel and similar work) for an API that NVIDIA and AMD were both uninterested in. And again, anyone could have made a Vulkan emulation layer on metal.