Tao: You make a good point on past market sales figures. Here is another one in your favor: Nikon has invested in upgrading that FX 80-200/70-210 2.8 lens many times without producing a DX counterpart. Why? The 17-55 2.8 may have "tested the waters" on the concept of 2.8 pro lenses for DX and found that market lacking. The market may have spoken and rejected DX "pro" 2.8 lenses. Case closed? Maybe for some. I don't contest past experience or history. Nikon may always keep the DX line "more amateur" and never produce the basic FX pro zoom lenses in DX size.
But past is past and not necessarily the future. I am suggesting a different future is now possible because of better quality sensors in the upcoming DX bodies: one may not feel a need to move to FX in the future because DX has become so good. I wouldn't if I could get the basic FX 2.8 zoom lenses in DX. I would just keep my DX pro glass and ride the latest technology wave of D7000 updates or D400 updates. It seems to me that would be the most cost effective. But there may be too few others like me. Those new DX sensors may not make any difference in the sales projections for a pro DX lenses equivalent to the 70-210 2.8. As I said before, it is just an idea: new thinking of new options for a new future because of technological advancements. We don't always have to let the past eliminate possibilities for the future. Market viability may change over time.
On the other hand, people like me may never be able to get what they want in DX and may just have to move to FX to get a native 70-210 2.8 zoom range. Hopefully, the new D4 and D800 will cause a large drop used FX body prices to reduce "the price of entry to FX" making that option less costly but you then will be shooting with five year old D3 era technology. It actually may be cheaper to get a used D700 body to use with an existing 70-210 2.8 lens than it is to get a new DX specific 70-210 2.8 equivalent lens to use with an existing DX body! That is another possible future and the market viability of how far and how fast used FX bodies may drop has been debated here in other threads. When the D400 is out it will be interesting to see if five year old FX technology yields better IQ than the latest DX technology simply due to the larger size of the FX sensor. Maybe so, maybe not. I expect to see that issue debated here when we can do so. It will come as: should I get a used D700 or a new D400 for about the same price? No one knows the answer at this time.
What has been true in the past may also be true for the future. But then again, not necessarily so . . . . . . which has been my point in many of the comments I have posted here.
