Guy, Bob and I were discussing this very thing over the weekend. Bottom line is most cell phones of today are better than pro-level 35mm SLRs we had 30 years ago. And everybody's got one, so "photographic images" are not much of a commodity -- nor are paper versions of images valued nearly as much as they used to be.
My Epson 7900 will likely be the last large printer I purchase. Why? Because very few people want prints anymore. I was in Costco the other day and they are now selling 50" flat-panel TV's in twin-packs for under $1000. My next house will have the walls covered in monitors that each have a dozen or so images cycling through them hourly -- changeable art and ambient lighting all in one. Heck, and a little free heat too :lol:
Finally, how much better can Nikon or Canon make an FX sensor? Not much, we are pushing at the edges of physics already. Lenses yes, and here is probably where we'll be seeing some efforts and they need to. But get ready to pay for them if the new 58 is any indication -- incremental increases in performance for 3x the price, just like it's been with audio gear for quite a while. Other option is designer cases, a-la the Df. Some will buy them at what appears to be a 2x pricepoint, and when sales drop off we'll see the same sensor, or perhaps the D600 sensor in another tricked out body -- and we'll buy that too. It's worked for Leica for years, and all it will take is for Nikon to get the feel for what their customers want in an accessory camera.
But at the end of the day, our cell phones produce images that are good enough for even the next generation of 4K displays, so my guess for the future is something like this: DX consumer DSLR's will taper way off and eventually fade as M4/3 has that covered outstandingly well in smaller packages and lighter weights. FX pro-sumer and pro will stay around, but at higher prices. And we'll see the small cameras packed with features taper away as cell phones get all those nifty features.