> only way to use Nvidia is intentionally either as an addon to a Mac Pro or as an eGPU, which they don’t see a large market for it
Not quite. From Nvidia: "Apple fully control drivers for Mac OS. But if Apple allows, our engineers are ready and eager to help Apple deliver great drivers for Mac OS 10.14 (Mojave)...Unfortunately, Nvidia currently cannot release a driver unless it is approved by Apple." — https://en.wikipedia.org/wiki/Nvidia#Apple/Nvidia_web_driver...
Apple is preventing Nvidia from releasing Mac Pro and eGPU driver support.