[citation][nom]BigMack70[/nom]it seems more plausible to me that they designed a GK110 gaming card (as rumored), had crap yields (as rumored), and then scrapped it for the time being since they didn't really need it performance-wise. They didn't need the high yields to make a workstation card, and now that they've had another year to work on their fab process, they can release it (albeit I'm sure in limited quantities) to the gaming croud.[/citation]
Yeah, probably...and now because the existing generation is so expensive despite being based on GK104, and because AMD doesn't have an answer to this yet, they'll jack the prices up as much as possible.
The 680 was supposed to be the 670 Ti, I discovered, but then something happened somewhere. I'm not sure if they had a GK110 based 680 or a derivative of it in the works, but then they must have realised they were equaling the 7970 (rather, the 670 was) so they probably scrapped it last minute.
EDIT: Here, have fun:
EDIT2: Never paid attention to the dates. It seems like 16 Feb 2012 is the approx date around which the decision was made.