Hey, this coin has two sides. Most of the illegal copying is done by people with no serious interest in the programs. Most people who illegally copy programs would not purchase them, when it means for considerable sum of money and lengthy sign-up and payment process. Therefore, if there is a way to sell programs with easy price tag and via authomatic painless process, it's possible to sell N times as much.

Where N is the "old" ratio between piracy and purchases.

That's how iPhone economy works.