I remember reading somewhere that they /did/ try to build some of the iphone 1.0 apps as something akin to dashboard widgets and found that the hardware just wasn't quite up to the task, and they were forced to build them as native apps for performance reasons. This says to me that ideologically, they were convinced that the osx dashboard widget method of development was the way to go, but the reality of mobile hardware, combined with their even stronger ideology of responsive user experience made them go native.