but Nvidia have plenty of room to drop prices IF the release of the 480 has any effect on their sales, in the meantime they can make hay while we still don't actually know that the release date of the 480 is the 29th of this month, just that the NDA lifts then
From a marketing point of view dropping your prices in response to a competitor always looks bad. Just like the way Intel's contra-revenue program where they were paying people not to use AMD chips looks bad. If you do it, you're basically walking up to the mic and saying: "our competitor was better so we devalued our product". Nvidia get a lot of sales out of their heavy marketing as "the best". If that goes pop, they wont like it.
Also, unless they have plenty of stock (which they haven't for the 1080), then many of the sales will be pre-orders and those will be cancelled in an instant if something better is announced in the meantime.