Petapixel recently had an article entitled "The Camera Industry is Trapped: Demand is There, But Products Aren't." The ongoing supply chain issues are creating quite a problem, from customer to dealer to camera maker.
But what wasn't said in that article is something that DSLR users are starting to fear. Basically, it boils down to this: with parts in short supply, the camera makers have to pick and choose which products they put them in. With Canon and Nikon both trying to transition to mirrorless and match up better against Sony's Alpha lineup, that means that critical parts are headed to mirrorless cameras, not DSLRs.
I suspect this problem has been around for a bit in different guises. The D500 and D850, for instance, have been in short supply for some time. We get small periodic batches of them hitting the shelves in the US, but they don't stay in stock for long. Indeed, B&H has started once again actively selling imported D500's, probably to make up for the lack of supply from NikonUSA.
Both the D500 and D850 use older versions of image sensors where the mirrorless cameras use newer ones. For example, the Z50 and Zfc use the same 20mp sensor base as the D500, but with enhancements. Thus, if Nikon has a fixed limit to the number of sensors they can get produced in a time frame and the combined Z50/Zfc/D500 volume exceeds that, guess which camera is going to get the short end of the stick?
This is one reason why I've been advocating for a D580 (and D880). By simplifying down to one image sensor as Nikon did with the Z6/Z6 II/D780, you have more flexibility to pick up some of those dedicated DSLR users who aren't going to switch to mirrorless any time soon. And I remind you (and Nikon): the D500, as it sits today over five years after being introduced, is still the best overall APS-C camera you can buy. Quality images, high performance, top focus system. Why would Nikon ever want to cede this Top Dog spot? Making a better D580 that holds the crown seems like a fairly trivial engineering exercise. The fact that it hasn't happened points to a strategic policy that dismisses the D500 over something that doesn't even exist in Nikon's mirrorless lineup.
Coupled with the on-going supply chain issue, that is what is now driving DSLR users' fear: that the current DSLR products are it. There's not enough parts to make new ones, and by forcing the issue of getting people to transition to mirrorless, Canon and Nikon are driving DSLR demand downward at the same time. At some point, this all becomes self-perpetuating.
It's not just cameras we're seeing dry up. EF and F-mount lenses are getting the same short shrift. Nikon recently cut production of the 70-300mm AF-P lens (it seems this might be temporary, but that's known for sure). Why? I suspect it's because it uses the same stepper motors that Nikon needs to deliver Z-mount lenses.
When DSLRs supplanted film cameras, that transition happened fast. Part of that was that DSLRs offered immediate review and didn't require constant media replacement. Customers caught on quite quickly to the advantages. Indeed, film SLR sales had not just peaked, but had dropped down to a lowish plateau in the decade prior to DSLRs appearing. DSLRs generated a whole new wave of buying, and DSLR sales quickly rose to far higher than film SLR sales.
The same thing isn't quite true of the DSLR to mirrorless transition. Not everyone sees clear advantages, and technically it's been eight years of (mostly) Sony trying very hard to get full frame mirrorless to DSLR levels, let alone above them. Moreover, what also doesn't get discussed much is the difference between consumer and prosumer/pro trajectories. Consumer DSLR has been in a nose dive, just like film SLRs made once DSLRs first came along. But the higher-end DSLR has not been in such a nose dive. Down some, yes, but I'd also argue that the camera makers themselves have been partially responsible for some of that downward trend. As in: today you can't buy a D500 off the shelf, so of course sales are down. Duh.
Another background point comes into play, as well: Canon and Nikon would rather stop making DSLRs. Why? Because the manufacturing process is so much more involved and costly. Sure, if we measured it dollars per unit we might still be in the single digits, but have you noticed that Nikon is saving less than pennies wherever they can (no hot shoe cover on the Zfc, for instance)?
So put all these things together and you get the great fear that dedicated DSLR users have: the camera makers are moving on, leaving the DSLR user behind. To put it into MBA-school terms: they've stopped milking the cow.
I really hope this isn't true. As you may recall, Nikon surprised the world with the F6 film SLR, which came after (and was based on) the D2h DSLR. For years this was not only the best film SLR you could buy, but it was about the only one. Clearly Nikon made not only money but brand reputation off that camera. I'd argue that they should do the same with a D580 and D880, and point to a DSLR road map that is solely D580, D880, and D6 as long as demand warrants. Last call on everything else, pointing to mirrorless for the rest of your needs.
