Either the Z8 or the Z7 III was going to be the increased pixel count camera. From a product line management standpoint, both choices have issues.
You may have noted that NR was confused about EVF pixel count. That's because multiple protos were circulating with different approaches in the new body. I wonder if Nikon went to the last moment before deciding which camera would get what? A Z8 with 60mp+ and a 9m dot EVF would be the D5/D850 approach, while a Z8 with the 45mp stacked and 3m dot EVF would be the D3/D700 approach.