Apple is positioning itself as _both_ a platform for applications and services _and_ as a consumer service. The services offered by Netflix, Hulu, Rhapsody, Rdio and so on offer value consumers have time and time shown they are willing to pay for. These are services the content owners (artists), studios and labels do not provide or provide poorly. Claiming they simply "repackage ... artist's content" is misleading.
These services are increasingly cross platform, available on the web, mobile devices, internet connected consumer electronics, game consoles, etc. They add value to those platforms and can complete when the platform is suitably independent. Those platforms provide only a portion of the necessary infrastructure to run a consumer service. Purchasing, bandwidth, hosting, encoding, transcoding, metadata, social networking features, inventory and so forth are typically still maintained by the consumer service itself. They already have these services due to their web presence.
Apple tries to play the game both ways in an increasingly monopolistic fashion. Before you go on and start harping about Android, recall that Microsoft was convicted not because it was the only operating system (it wasn't) but because it used it's market advantage in the OS to restrict competitors in other markets (browsers). Apple is doing the same thing.
It's one thing for Apple to provide competing consumer services. It's another when they intentional block competition on their supposedly independent platform. Keep in mind, as a platform provider, Apple doesn't provide as many services as Zach suggests. They are little more than a payment services provider, though their rates and restrictions are completely out of line with the rest of that market.
Consider for a moment if Apple were to do provide the same APIs and restrictions on all of Mac OS. Applications can only be made available in the Mac App Store. Applications must use Apple's subscription and purchasing API and no other API for purchases. And so on. They have their own browser? Why not offer an API for web apps as well. It would be secure and user friendly.
"Apple takes the place of publishing, distribution, inventory, sales, payments and shipping... Seems reasonable to me." I'm sure it does.