Apple announced some time back the these legacy technologies would be replaced with Metal (not Metal 2).
To say there is no VR in macOS is ignorant, Mojave is full of resources.
Apple has established a "professional users" group of industry leaders to lay the roadmap for future pro app development. So that argument is ignorant of the facts, also.
Linden Labs has known about Metal for a long time, and can choose to move to it, or not. If they do, they'll be able to easily build a SecondLife viewer for iOS, also. It would be very short sighted of them not to. And since Mojave is still only beta now, no one is releasing apps publicly for it. You'll see that after the public release. It has always been this way, for any OS developer. The panic in this thread is unfounded.
But I'm just a retired IT engineer, what do I know?