650 $ is more accurate i think. However, in term there is highly overclockable RAM added and a aftermarket cooler, its possible to have it even higher priced. Its simply in the range of a 780 GTX, so im not surprised at all.
I would say, the performance when aftermarket stuff added and when RAM is at 7000 MHz, it may be exceeding Titan performance (and equally clocked 780 GTX), so it could be well worth the price tag. Althoug i dont expect Nvidia to drop prices, they can sell even a dog poop...
Finally, have to take into account, up to christmas there will be a lot of shortage because there is simply not enough of chips available. So it wont be helping the price and the manufacturing is not cheap at all.