Michael Tsai, rounding up a couple of stories on the lack of NVIDIA drivers for Mojave: No NVIDIA Drivers for Mojave.
Apple fully controls drivers for Mac OS. Unfortunately, NVIDIA currently cannot release a driver unless it is approved by Apple.
I don't have strong opinions of NVIDIA as a company, but I do like their graphics cards. I build a PC with a GTX960 a few years back to give myself an affordable video editing machine a while back. Apple's intransigence - if that's what it is - is somewhat confusing on this issue.