All these auctions have been trolled by people who drove up the price and then backed out of the deals. They left the vendors hanging for several weeks. In short; none of the high prices you've seen of late have been actually paid.
THESE MARKET VALUES ARE NOT REAL VALUES.
If you have one to sell, don't put it up for auction, use Buy It Now. Go Dutch auction if you will, but don't waste your time with a bidding auction.