Now you asume that most photographers fall for the bling of the 1DX III. A few weeks or months after the release of the Canon, I would have to search the internet to remember what those amazing features are. They are not important to me for that kind of camera, so easily forgotten. As a Nikon user, the D6 is much more significant, although it would have been nice if it had better live view and video AF like the D780. However, if I'm going to use live view a lot or need very high quality video, I wouldn't use a D6 at all, but a smaller, lighter camera like the D780 or a mirrorless.
Nikon has always been the maker of serious, boring cameras, and with some exceptions, they are rarely first to the market with new stuff. If they will survive or not with that product philosophy, nobody knows, but I'm quite sure they will never become Sony, not unless Sony buys them.