In the economic climate that the camera market resides in, it just doesn't make any sense to maintain more than one system.
Chief Editor - opticallimits.com
Doing all things Canon, MFT, Sony and Fuji
Well, there are no official specifications (other than that is has a stacked sensor, which is all about readout speed and potentially offers quite some processing power at sensor level already), at least not the kind of details we're all waiting for. But there's a somewhat solid set of rumors that looks promising and there have been interviews, where between the lines one could read that the Z9 is the next big thing after the D6 (and expected to outperform the D6 in many ways). Plus the rumors about some long tele primes... even though they are probably going to be even more expensive than the current long FL primes.
We all know Nikon is struggling a lot. Even without corona, they would probably not have enough resources to keep developing and releasing products for both mounts.