Then again, it's hard to make a case for not learning OGL. You still need to learn all the concepts whether you'd end up using Vulkan or Metal or whatnot.
At worst you'd end up having to use an OpenGL middleware thing in the middle of you and the lower abstraction level API. Like yes, OpenGL is crufty. It's also just not good in many ways, but in many ways it's simple. The lessons learnt from it also informed Khronos on the design of Vulkan, so even for that, it's nice to be able to see just where some of the design decisions come from.
Also, not everyone develops for Apple and so their deprecation is less compelling than, say, Khronos officially stopping development on the API ;)
At worst you'd end up having to use an OpenGL middleware thing in the middle of you and the lower abstraction level API. Like yes, OpenGL is crufty. It's also just not good in many ways, but in many ways it's simple. The lessons learnt from it also informed Khronos on the design of Vulkan, so even for that, it's nice to be able to see just where some of the design decisions come from.
Also, not everyone develops for Apple and so their deprecation is less compelling than, say, Khronos officially stopping development on the API ;)