If Best Buy doesn't sell the software, they lose money, because A. They already paid the developer for it. B. It takes up space that could be used to sell something else. If Best Buy wants to sell it at a discount, it doesn't affect the developer, they were already paid by Best Buy.
With Apple, its the opposite. If Apple sells something at a discount, the developer suffers (or Apple has to pay the difference in some countries). If it doesn't sell, no one gets any cash. Apple has no incentive to market something and/or move inventory. Apple has only the incentive to market things that you spend money on vs. Best Buy that has to take a risk on something by spending money to buy it from the publisher first.