The average App Store customer buys less than $20 worth of apps last time I saw numbers quoted. 30% of $20 is $6. Apple is a hardware manufacturer that sells $X00 phones at one of the highest markups in the industry and also gets a kickback from AT&T for every customer they bring to monthly billing.
Apples' incentives are almost totally non-related to developers' incentives: their primary interest in apps is to move more hardware and contracts.
Okay, how many of them are making a serious profit? How many are breaking even? How many are profiting primarily due to an existing customer base? (I'm thinking of Pandora as an obvious example; they're making money off of Apple's platform, but they were making money before they wrote an iPhone app.)