Actually HDD pricing is essentially price discrimination. They are making the core/hardcore gamers who are willing to pay more for the best experience on the console pay more essentially. They stated a while ago that they broke even on the Arcades with accessories so you could probably conclude that the base cost for the Arcade should be somewhere around $220 and the cost of the Premium should probably be $260 as the difference in HDD costs are no more than $40 and the Elite would cost at most $280. They do what they do to maximise total sales/profit. If they prices the HDD at less they would probably have to charge more for the Arcade and they would have to charge less for the Premium.

there were shortages almost every year except maye 2008-2009