From 2012 to 2014, even before, Apple produced millions of Nvidia-based devices.
Since high sierra, Apple have officially supported eGPU only for AMD-based or iGPU-based devices.
Just for competitions between Nvidia and AMD, bad relations between Nvidia and Apple, Apple intend not to support eGPU for Nvidia-based devices, but Apple can fix it easily as long as they want.
In MACOSX 10.13beta4 and below, because of mac_editor’s hard working, there’s a compromised workaround. But from MACOSX 10.13beta5 and 10.13 official, Apple modified several hidden kexts of the kernel intentionally, so even a compromised one is not applied usefully. And Nvidia made the web driver totally non-functional for eGPU with black screen which apple official may just pop out eGPU notification but unconnected.
This should be solved long long ago by Apple, not considering Nvidia for the above reasons. But both did nothing!
IF Apple just for thunderbolt3-based devices, I will not grumble for this.
BUT you even support thunderbolt1 or iGPU devices.
THIS IS DEFINATELY DISCREMINATION!!!
At least, Apple totally completely could disable Nvidia-eGPU and turn Nvidia-based macbook into iGPU-based macbook, which is already an existed model.
This situation happened just because Apple never think about this issue severity.
PS: IF anyone Apple staff deletes my post, I will email Mr.cook again, Apple exective liaison from Mr.cook office just contacted me.