And consider the pattern: WebObjects -> Apple Online Store -> iTunes store -> Apple TV -> App Store -> iBooks -> ? If Apple invests in a new feature for their

And consider the pattern: WebObjects -> Apple Online Store -> iTunes store -> Apple TV -> App Store -> iBooks -> ? If Apple invests in a new feature for their app/music/book stores, or in infrastructure, the costs and benefits will often be spread among various businesses. By contrast, a phone competitor setting up an App Store probably doesn't have this. Investment in their App Store just benefits the App Store and whatever portion of their products is able to use the App Store. I think if you look at Apple's business, you'll see several 'virtuous cycles' like this. OS X / iOS is similar. Investment in OS X may eventually be carried over to iOS when the iOS hardware can use it, and features developed for iOS, like Core Animation, can migrate to OS X.