Wait..
the article itself states that Nikon announced the development of the Nikon D6, just because it was expected doesn't mean it doesn't count, does it? That's the professional, sports and wildlife photography market. So it's safe to say the F mount is going to be around for yeaaaaars despite the new Z series.
Nikon has pro, prosumer and entry-level DSLR. They also have compacts and now they've entered the mirrorless market. However it doesn't seem that they hope to convince their professional consumers to switch to mirrorless (some features like battery grip with buttons, dual card slot are missing) ... so their plans aren't clear, besides entering a very, very competitive market..