erick, RV670 is *not* the HD 2900 Pro, and has not been released yet. RV670 will be released in November... You can't deduce its performance based on R600 benchmarks...
As for NVIDIA not doing things for "progress' sake" - yes and no. They won't reduce prices just for shit and giggles. But that won't affect their product roadmap at all: if competition is weaker, they'll price the same products higher, and that's all.
If NVIDIA or AMD can replace a chip by a new one on a lower process node to save money, they'll do it. If both do it at the same time, then logically they will both lower their prices accordingly; however, if only one does it, then prices will remain higher. In a highly competitive market such as GPUs, however, the former is more often true than the latter IMO...
As such, I still believe that G92 will (eventually?) replace G80 completely. I don't know if it will at launch, or even this year; but I don't believe in the G90 rumours, and there is no reason for NVIDIA to keep a gigantic 480mm2 die longer than they need to. Whether the GTX/Ultra will be replaced by a higher-end G92 SKU or the G92-based GX2 is the key question at this point really IMO. And as I have hinted at earlier, this depends solely on whether NVIDIA is willing to use GDDR4 this round.
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