You can always just buy a 2019 Mac Pro.I find it amusing. How would Apple start supporting nVidia again, when they even ditched their long tradition supporting AMD?
From my read on the situation, Apple is comfortable focusing the research and development on their own chips, period. And it does not matter to Apple, that part of the customer base relied on the graphical capabilities of other producers.
Even if I prefer the older Intel era macs. I can very well imagine that several years from now, that I too will be happy to purchase a mac based on future versions of the Apple M-series.
They will be supported for a LONG time.