Or Apple could have simply implemented something similar to the Service process used in Android. A service is scheduled and will run as long as resources (memory, battery, etc) are sufficient to keep the high priority processes (the UI currently visible, etc) running. If resources become low, Android can kill off Services as needed. And there you go, no degradation of user experience.

I am curious as to the real reason why Apple neglected to implement a Service capability. The iPhone is effectively not multi-task capable and that is a monumental shortfall. I can only guess that they had too much to implement and didnt want to take the time (at least yet) to implement the service scheduling properly. Or I give equally likely probability that they simply dont want 3rd created applications to rival what Apple can make. They seem pretty anal about maintaining tight control over their walled garden.