I'm sorta w/ ryheeles here. I don't see how Amazon has any obligation to offer $20+ discounts on new release games, or to sell items at a loss, or do anything if it's a money-losing proposition. You can't expect amazing deals from a single retailer to come all the time, because at the end of the day, it's all about profit margins.
I've gotten plenty of awesome videogame deals from Amazon over the years, with many a $10, $20, or even $40 dollar promotional gift credit for buying games, but I realize that they're a business that's trying to make money, and they can't offer large discounts or credit offers on EVERY game or ALL the time. I'm just happy when they do offer great deals, and if they ARE not offering a great deal on something I want, then I take my business elsewhere. Simple as that.