I appreciate the time and thought that was put into the discussion on this topic. Lots of interesting and provocative posts.
My own take on the topic is in line with most of you. I think Roger's article is on the money and that lots of things probably will change dramatically over the next 5 years.
Personally, I don't ever see how a DSLR will lose its place in the photographic community. I think that there will always be a demand for quality photos, thus quality equipment must be there. But, that doesn't mean that the high sales numbers that Nikon and Canon et all, have enjoyed over the last decade, will continue. I expect to see the DSLR market shrink back to the levels of the film days or early digital days, ie the d1 & d2 eras.
In the early digital days, Nikon only had 1 "consumer" body, the d100. Then the d70 came along, starting the consumer rush. I think we'll go back to the point where Pro cameras outnumber or equal the number of consumer cameras.
Why? Because a DSLR can do things that no other camera can do, at least at the moment. High speed, focus accuracy with subject isolation, is never going to go out of style. Sports, wildlife, action shooters comprise a large portion of the market. Nothing other than a DSLR will do for that market.
The only question is whether or not Nikon and Canon see that market and are willing to fight for it. Right now, the other makers are catching up. N & C are the leaders in PDAF, high speed, high accuracy AF. That's not a trivial feature. But, the other makers will figure that out sooner or later and it seems that they are working on it.
Nikon's main business is photography. To survive and be relevant in the marketplace, they must dominate the high end market, which would include the high end DX market. The d300 and 7d have been the TOL DX cameras for years. I suspect that both N & C were satisfied with that, which is why I think the d7k series has been Nikon's focus. It's good, but not better than the d300, until now. But also, now the competition is putting pressure on that market segment. The time has come for Nikon to consolidate their bodies or decide if it's worth continuing in the business.
I'm hoping that they decide to continue and offer a truly great DX camera soon.
For the masses, a smart phone is probably going to be sufficient. I see tons of images, every day, taken with a phone and many/most of those images are truly awful. But, for the moment anyway, they seem to satisfy the casual user, which to me, means the death of the low spec DSLR.
I don't know what will happen with the so-called "enthusiast" market, meaning that I don't know how deep it will be. Maybe they'll go back to the 1 or 2 consumer camera model that they had in the film and early DSLR days.
Kerry