Yes, it's probably not appealing to the general population, but there are many folks who truly love "old glass" and don't mind working it manually. It's a subjective thing. And as Mike S mentions, current Nikon bodies with the internal focus motor will autofocus back to at least the D-series and have some control functionality over AI lenses (even older) that are properly prepared. Given that many folks don't switch camera brands much, if at all, we're talking people who have been using this stuff for many decades. When I bought my D750 a few years ago, I still had a 50mm lens from my original Nikon film camera I bought back in like 1979. It actually worked fine for metering, but, of course, was manual focus. I put that on the film camera I picked up for my daughter to use for her high school art class. (black and white and they had to develop them themselves in the school) The new Z-series mirrorless come with an adapter that lets one use lens back to a certain point, too, although not as far back as my D750 and Mikes D850 can handle.