First of all, the fact, that GK104 is a chip meant for a midrange card was obvious from the beginning.
AMD did not have a solid product at all if it could be beaten by a midrange chip. NV even commented on that and you guys were laughing at them.
NVIDIA sure did use the situation to their advantage, because why not.
I agree that we'll probably see the GTX 680 in a limited supply, because they will be using the fully enabled chips on the GTX 690 for higher profits. The GTX 670 will take its place.