Are they out of stock and need their full capacity for the Z-System and cant do further production runs?
From what I've heard (camera stores), the Z system is selling poorly (stores have had to dump Z products at below their dealer cost to get rid of excess stock) and it seems unlikely that Z lens production is taking the place of this lens. Since the 200/2 is widely in stock, I suspect the problem is simply that people are not buying it and thus it is discontinued.
IMO the 200/2's VR system is outdated compared to the more modern lenses and so is its autofocus. It focuses very fast but with a lot of variability in focus again compared to more recent AF-S lenses. In more recent FL lens designs Nikon have been improve both a lot and I think the lens is due an update. People also think it's heavy and front-heavy (by modern standards, certainly) and this affects its usability. An FL redesign is overdue.
However, it has a unique signature to the images and is the nicest of all the lenses I've used in terms of how the images look. I don't think this lens should be so easily abandoned. If they are about to introduce a better lens, by all means, but it's good to let the customers know if it is coming or not.
Was this planned or is this part of an emergency reaction to Covid-19 pandemia and the foreseeable significant drop in demand for photogear?
As COVID-19 affects travel, photography, events etc. all of which are major reasons for photography to take place, it is obvious that camera sales are taking a hit. However, this is true of many other businesses as well, as in crisis people are more cautious with the use of their money. And mostly it is the groceries retail business that is doing very well. The Tokyo Olympics are postponed until 2021 and the 200/2 is of the kind that might be used there, so Nikon could launch an FL version by next year. I do a lot of my photography with fast short and medium tele primes, and Nikon seem to think that 70-200/2.8 is almost all that anyone could ever ask in this focal range (look at the Z mount roadmap; no fast tele primes longer than 85mm). I think the opposite that these fast prime lenses that have pleasing rendering are the most useful to me. And I don't consider the zoom the equivalent of this lens (or e.g., the DC 105/2).
Were there ever plans to replace this lens with a new FL (SR) or something (patents for 300 and 200 mm FL teles were reported) version (that plans might have changed now) or is the new 120-300 mm not only dedicated to replacing the 300/2,8 but also the 200/2
The 300/2.8 is not listed as discontinued, though this might change in the future. Since a Nikon patent mentions a design for 200/2 FL, it seems clear it has been on the drawing board.
I don't like to say such things but I think the 120-300/2.8 is priced beyond reason and if Nikon indeed think that it's a replacement for 200/2 or 300/2.8 then I will have to reconsider which brand of equipment I buy in the future. 11400 € lenses are outside of the reach of most people. And normally one has to always be prepared to produce a backup that yields the same result should some piece of equipment malfunction. So make sure you have two.
Since Tokyo Olympics is delayed and basically all sports events have been cancelled for quite some time, I think Nikon will have a really hard time moving the 120-300.
