Guessing what the Nikon camera lineup will look like in the near future.
I just can't help but wonder... as the new Z-series bodies are kinda entry-level bodies if we look at the form factor and controls. Top quality sensors inside sure, but controls are like directly from a D3200. I got this crazy idea in my head that the Z6 is the upgrade/replacement to the D610 and Z7 is the successor to D750.
Otherwise new D620/D760 would cannibalize the Z-series and/or vice versa. And what else Nikon could add into the D600/700 series anyway? Higher FPS and/or higher resolution would make them step on the toes of D850, so it is a no go. And Nikon is such a small company it cannot hold 7 concurrent FX bodies in the lineup. I personally assume that DF is discontinued as well as D600/700 series. They all share the same mirror box and chassis, so they have probably been manufactured on one assembly line. Sure, plenty of all of them in the warehouses all over the world, but manufacturing has ceased several months ago.
So the current FX lineup is D5, D850, Z7, Z6 and that's it. I wonder if/when Nikon starts consolidating the 4 lines of DX cameras into fewer lines. At least the D7500/D5600 pair is probably a bit redundant now, so the next model to replace both could be a D6500 with flippy screen but without in-body AF motor to cut cost, size and weight. That would mean the DX lineup is D500, D6500 and D3400.
It's noteworthy the published Nikon Z-line lens roadmap contains no DX lenses. The roadmap extends to year 2022 so that's 3½ years in the future. My guess is that there will be no crop sensor Nikon Z body, probably ever.
But what will be the next step? Will there be a D860 or will it be replaced by a pro-level Z8? How about D5? Almost certainly a D6 will be released for the 2020 Tokyo Olympics, as it is too early for a pro sports body Z1, especially as the roadmap doesn't contain any of the sports lenses for the Z-line: 200/2, 300/2.8, 400/2.8 and 600/4. As a matter of fact we are so close to the Olympics now that probably early versions of D6 are already been manufactured by hand, one by one, for internal testing, and also a new assembly line is being tooled and being put together. A camera and the factory to produce that camera does not happen overnight, the process takes years.
But... after D6 sometime in 2022-2024 timeframe we will probably see a pro sports Z1 which could mean the demise of the Nikon FX DSLR line, if (big if) the sports lenses are ready. Otherwise a D7 is also a distant possibility, and it will be the last of the mohicans.
Final guess, Nikon camera lineup in January 2021:
D6, Z8, Z7, Z6 and D550, D6500.