The real success of the Apple App store is not the money, but the way it has changed the software industry. Apple provides a stable open platform for developers and hundreds of thousands of developers to create innovative solutions, and more importantly maintain them.
Contrast that with Enterprise software (the industry I work in) that struggles to release 1-2 upgrades to an app per year, that are so complex that users need classroom training to use it.
(1) You rarely get products right the first time; success comes from iteration and evolution. Ergo, a successful platform must enable rapid iteration and improvement.
(2) Our experience with Seeking Alpha’s mobile apps: Google’s platform allows for faster iteration and evolution than Apple’s.
(3) Thank you Eli Hoffmann for the tip.