This shows exactly how little you understand about what you are talking about. GPU rendering is only for a relatively small market compared to CPU(despite Nvidia desperate marketing attempts that tells you GPU renderer are 1000 times faster than CPU). Tell me about a single Hollywood blockbuster movie made using GPU for final render? There is a reason why you won’t see that anytime soon...
Like many other users I’m going to render on my next machine, using mainly CPU like I’ve done for the latest 20years(here is one of my scene:
https://forums.macrumors.com/threads/highway-robbery.2199405/post-27800842 , no way you can render that on GPU since it lacks sufficient RAM and features). Even if GPU renderer become suddenly viable for every kind of scene both Octane and Redshift(the biggest player among GPU engine) will support AMD cards.
So yes, we will use MP for rendering and the (eventual) lack of an Nvidia option doesn’t matter. Also Mac hardware is not only for running Apple software, this is just ridiculous. Apple actively works with other developers and support other software, including Maxon, Adobe, Otoy, SideFX, The Foundry, Black Magic, Autodesk... and well.. most of the other creative software producer.