The other interesting data point is the bidding for the new TLDs in summer 2012 (http://www.marketingmagazine.co.uk/news/rss/1136468/Amazon-G...). Amazon and Google bidded on 150+ new TLDs between them. Apple? With $120bn in the bank, they applied for... .apple. Even Microsoft understood the potential importance of this more than Apple (they applied for 5 or so - .live, .docs, .bing etc).
Yeah this is the thing exactly. Amazon and Google are essentially content plays in mobile. Devices can come and go but as long as people are using their services they're making money.
Apple is a hardware play and that gave them a big first-mover advantage but unless they can keep coming up with iPhone/iPad level home runs that advantage deteriorates quickly. I will never buy anything in iBooks, for example, because I don't want to be limited to Apple's devices to read my books, even if I do currently have an iPhone, iPad and MBA.
They do have some platform tie-in with iTunes Music but the writing is on the wall there. Subscription models are the way forward.
Same for magazines and book. I keep a few subscriptions but mainly consume the content once. When I find a good book, one I will read again I put it on my library shelf and come back to it later. Subscriptions for media lock me into a singe channel if I ever want to go back. And like Netflix, who has to negotiate with the content providers for their content, with subscriptions there is no guarantee the 5-10% of quality content I like will be there when I come back.