I'm more thinking the reason the gtx 470 and 480's aren't exactly in the right price points is since so many poeple bought one they figure they can still sell off thier stock to people looking to sli them.
as for the earlier mention of the 6770 doubt it will be out for at least another couple months, amd has already said the 5770 will be aroudn for a while , and as it already beats the gts 450 stock there's no reason to replace it until close to the gts 550 release
there will however be the 6990 here soon another dual gpu undissputed king of the hill, i guess nvidia is ok with thie single chip crown and amd is fine with the dual /overall crown ... thogh there are rumers of a dual card based on the gf104's perhaps its a dual gtx560 card who knows