http://videocardz.com/nvidia/geforce-600/geforce-gtx-660ti
RELEASE DATE:August 16h, 2012
and as you can see the price drop to ~$300 was announced august 21st and hit the market around that time, after the 660ti was released and the pricing history in the graph obviously shows the announcement wasn't late but happened at the same time.
maybe your price checking wasn't as thorough as you thought . . . my point of those great prices on the 7950 because of the 660ti still holds. (thumb that)
How many times do I have to remind you that the price drops was announced by AMD late? Or it could be the fact that at a week or two before the 660ti was released, all graphics card manufacturer(Asus, MSI, Saphhire, etc) drops the price of the 7950 themselves since you could find most 7950 at $320-330, but I find that hard to believe so AMD themselves must've lower the MSRP and had not yet announce it to the public.
The same thing happens today (although I don't know whether it's AMD or the card manufacturer), where if you browse Newegg right now, you can find the 7950 at $310 or even below $300. As far as I know, the MSRP hasn't changed yet from $320 and there's been no word from AMD about this either.
My conclusion about this, is that the 660ti is still overpriced considering the fact that once you take high resolution, higher AA settings, multi-GPU+multi-monitor setup and higher overclocking headroom, the 7950 pretty much trumps the 660ti in every way for a card that can be found at the same price or just slightly more expensive.