From my personal point of view, Nikon's failure to press forward with a mirrorless system was the cause of my moving to Fuji. I have the V1 and the AW1, but these cameras had control systems which seem to have been designed to put off enthusiasts. It may be that they were trying to protect their DSLR business, but if so it was a significant error of judgment. Had they developed the I range properly and introduced the Z range sooner, I would still be a Nikon shooter.
Well, the issue now after they introduced the Z is that their sales are falling faster than before because during the time they don't have complete Z system many customers will wait for a more complete system and because the Z has nevertheless been launched, many have stopped buying F mount equipment. If Nikon had launched the Z five years ago, their fall would simply have been accelerated (since it would have taken a long time for the mirrorless sales to pick up the lost DSLR sales). With mirrorless, companies start largely from scratch building new systems so companies that had previously good positions in the market will fall from a high place. I don't see how this could have been avoided. However, in my opinion the Z products are really nice; I especially like what they've done with the optics and handling of the cameras. If people simply give Nikon enough time to build their new system, I believe they will eventually do fine. Personally my enjoyment of photography is dependent on the optical viewfinder and I don't contribute to the chaos (bought two new F mount Nikkors this year). I get the advantages of mirrorless cameras (and use some micro four thirds cameras at work for photogrammetry and video) but don't currently own one for personal use. I will eventually buy a Z camera and lenses because I like some of the lenses they've come up with but not now. I've spent money on new computer hardware and ligthing tools and can't really afford the purchase of a new system of cameras and lenses at this time. The low-light AF also has failed to impress me in the Z7 from what I've tried it. I think it can be solved using the following way: when the light is low, low enough that the data is too noisy to focus using, offer the user two options: increase focus area size (less precise AF point control but by spatial averaging, reduce the noise), and increase integration time (slower focusing but noise in the AF data is reduced by temporal averaging). I believe that both of these can be implemented using current hardware simply by working on the algorithms. They also need to offer "nearest subject priority" such as currently offered by group-area AF in DSLRs; this doesn't allow the photographer as precise pointing of the exact position on the subject to focus on, but by considering a larger area (5 points in Multi-CAM 3500; up to 13 points in Multi-CAM 20k?) the system is able to focus on subjects in dimmer light and can handle faster movement. Something that they also need to work on is focusing based on subject recognition (eye AF is an example of this) but to make that perform really well, they might need to improve the processing hardware as well; not sure what the bottleneck is. Anyway I am sure that Nikon know this and are working on solutions to the problems. Once they do, I believe the Z sales will pick up.
If Nikon had abandoned F mount system development I would probably have sold my stuff and moved to Canon or quit photography altogether (I really would prefer not to buy more than one system in a lifetime, as it is wasteful to have to spend a lot of money to barely stand still or drift backwards), so it's not clear how to keep all customers using only one approach and one product line. They need to look at diverse photographer needs and address them as well as they can. I think the main issue with Z is the AF; the lenses are great and the bodies are nice to use, and it only takes a couple of years to have most lenses that most people need available as native lenses. Even with the current AF for many subjects it works fine, it's mainly just the edges of the performance envelope (low light and fast-moving subjects) that need work. Some photographers have moved to Z7 and note the Z7 focuses more accurately than DSLRs for long-distance subjects, for example. I don't quite understand the negativivity, except that negativity and provocative comments get noticed and result in clicks. It's like people enjoy feasting on someone's misfortune.
Ultimately, it is not about any of our individual personal preferences, but about what the market wants; and Nikon got this wrong. I hope the Z series will be a great success.
I disagree, there is no "one market" which can be addressed by making a certain type of product, but many different users with different needs and preferences.
I do agree the 1 series was a mistake but then even that is not so clear looking at how well Sony are doing with their RX100 series of compact cameras that feature many of the 1-series features that Nikon were pioneering. Basically the market for that kind of small-sensor camera with high fps and fast AF is still there, but with a fixed lens rather than interchangeable lenses. No one has a crystal ball that can see what will happen in the future. ILC users predominantly want larger sensors, that much has become clear.