I doubt that this will be reflected in the used market situation in the short term. Eventually when a more complete set of native Z mount lenses is available, yes, only partly compatible lenses may lose value but this will take many years. Many people already sold their AF and AF-D lenses years ago when AF-S became available. Some are still using them with DSLRs. E.g. for the 200 AF D Micro, it works fine as a manual focus lens for macro (so AF-D makes little difference apart from short throw). Another lens I still have is the 105 DC which I have no intention of ever selling.
If anything, the new Nikon mirrorless and FTZ adapter can help maintain or even increase the market value of compatible lenses, because in the past few years people looked at the adapters available for Sony (Canon adapters to Sony worked better), they looked at Nikon's poor DSLR LV and video AF (Canon have had dual pixel AF providing good video and LV AF) and assumed the worst about future usability of Nikon mount lenses. I believe this is one of the main reasons why Nikon lost market share and Canon and Sony increased. Now that we can see that our existing AF-S/AF-I/AF-P lenses can work fine on Nikon mirrorless cameras, this has the chance of increasing Nikon's status in the market and the attractiveness of their F mount lenses as well. That some features are missing from the first Z6/Z7 cameras isn't really relevant: fully functional autofocus has been confirmed and we can just wait for the right feature set to appear on mirrorless, to use our existing and new lenses on them, and to gain fully functional live view and video AF, silent shutter capability with viewfinder, stabilization using non VR lenses and all the other new features.
So, maybe screwdriver AF lenses lose a bit of value on the used market - or not. Because the new mirrorless can have the chance of putting Nikon back on the map again, the price of even partly compatible Nikon lenses such as AF (D) Nikkors may increase. Even AF(D) lenses gain stabilization and new focusing aids in the viewfinder, so perhaps they will become more attractive than they were a moment ago.
