I very much believe that Nikon will continue to compete in the Pro/sumer DX arena. The capabilities of current sensors and processors are already delivering IQ beyond what had been considered pro level just a few years ago. There will always be professional or artistic applications which require the capabilities of larger sensors, but they become fewer as the DX capabilities improve. How big are the prints of a wedding going to be anyway? How much resolution do most publications actually print? In terms of IQ, A current FX camera, such as a D800, is more the functional equivalent a medium format camera of a few years ago, especially in low light.
There are compelling reasons for a pro build DX camera, beyond the cost of the FX alternative. Its the size and weight of lenses. I can take a couple of DX bodies with every lens I will need in my carry-on bag and still have room for a weekend's worth of clothing and toiletries. Do I absolutely need it to be a pro-build body, with the added ruggedness, dust and weather protection and instant control access? Well, no, but I want it, I'm willing to pay for it. There are a quite a lot of D200's 300's and 300s's out there. They seem to have put their money down just as I did. There are also quite a few "graduates" of the higher end consumer bodies who have out grown the need and desire to have an icon of a flower or a mountain to help them decide how to set their camera.
These DX pro bodies are higher margined than the super competitive, commodity priced consumer cameras. They do not need to be in an endless, irrevelant feature and pixel war. They address a more sophisticated market which wil pay a few hundred dollars more to get what they want.
I'm waiting. I've been a Nikon photographer since my first Nikon F, but they are a company, not my family. They once completely dominated the 35mm pro market. There sure are a lot of big "white" lenses in the photo press boxes now.