The business argument would have been "you can't maintain majority market share with such tight fisted control of the app store, approval process, choice of carrier, etc".
Choice of carrier is a serious issue. The other things? Not so much. The vast majority of iPhone users neither know nor care about the App Store approval process, and there's a more-than-sufficient number of happy developers out there to keep the App Store humming indefinitely.
Choice of carrier is a serious issue. The other things? Not so much. The vast majority of iPhone users neither know nor care about the App Store approval process, and there's a more-than-sufficient number of happy developers out there to keep the App Store humming indefinitely.