I was wondering, like how some of us have, on why Nikon would make a DX prime when cameras would likely be FX in the future. Thinking about it, I now think this is actually a good strategy.
As technology improves, new technology shifts older technology downward. For example, the Sigma DP1 has a bigger sensor than most PnS cameras. I believe Nikon is targeting that market of people moving from a PnS to a DSLR. As prices of entry level DSLRs drop, more people are likely to make the shift, and when they do, there should be a base of lenses and accesories for them. The DX format in the future would likely be like PnS usage today.
Today, I can almost safely say that every household has a digital camera, be it in their phone, a PnS, prosumer PnS, or DSLR. 10 years ago, this were not so. There is a large market to tap on.
In fact, with the release of the 35mm DX lens, it now becomes more appealing to get a D60. I can also now tell one of my friends to get this lens to couple with the D40x.