Unthinkable as it might have sounded a year or two ago, this isn't necessarily happening anymore. For instance, before this week's announcement of a new CBS News apparently introduced the app first -- or at least concurrently -- on the RIM Blackberry. The same app will be available later this fall for Android and Pre. Other examples are plentiful.

In fact, some app developers are now finding it so hard to make money on the iPhone platform that they're leaving it behind entirely, in favor of other platforms in either the mobile or non-mobile space.

For one, has just quit the iPhone fold, selling his Fitness Track and Emergency Information apps to BitBQ's Patrick Burleson. According to Macworld, Williams complained that iPhone app development is "too much effort with too little reward when compared to distributing software on my own terms on the Mac platform."

Maybe Apple's new in-app purchase feature will help curb any emerging iPhone developer bleed.