Apple has made sure you won’t be running 2080 on your Mac.
Nvidia doesn’t have drivers and by the looks of it they won’t do anything soon.
Seems like they try to close Nvidia out of Apple ecosystem and Nvidia also plays a chicken out game.
Anyway, indeed overpriced eGPU no doubt.
I hear Nvidia are working on their ”Web Drivers” for Mojave at least. Maybe it won't include support for the 20xx initially, but since they added support for 10xx I don't see why we shouldn't see support fort 20xx too eventually. Especially now when MacOS has proper eGPU support. We'll see what happens…