Last few games that have come in have been crap - the last one actually looked like a former redbox rental.
I wonder if it depends what region you are in or what shipping center that are coming from?
I don't Amazon is giving Xbox owners the shaft. Target made some sort of deal with Sony and Amazon just price matched for a few hours. If Target had the same agreement with Microsoft and we saw huge discounts I am sure Amazon would have caved in again and price matched.