OpenGL can't be deprecated, just like IPv4 or HTTP.
That combined with the fact that VAO that came in version 3 is the last feature makes all threats to force you to update weak at best.
As hardware peaks you can stop worrying about new things and write software that never goes bad.
The wheel has not been rediscovered for a long time. Focus on the vehicle instead = bike.
Yeah, I bet apple just wants to discourage project managers and other deciders from using OpenGL and adopt their new thing.
In the end, those strategies will require more work from developers, and those developers become "locked" on apple. It's a shitty practice.
Wouldn't it make more sense for the developers to target something more universal like Vulkan and then add an abstraction layer like MoltenVK[1] to make it work on MacOS if needed?