Forgotten in the discussion of fragmentation is that the MacOS and by extension the iOS ecosphere are forks of the Unix world which has also been highly fragmented. By forking it once again to create MacOS and tightly controlling their branch Apple has created their own little golden castle. This is exactly the game that Amazon is attempting with the Kindle Fire and to a lesser extent B&N with the Nook. The question is if either of them will be able to create the kind of differentiation that Apple has. I can see this (over the next 3-5 years) coming down to 4 players; Apple iOS, Motorola Android, Amazon Kindle, and Nokia Windows Phone (or whatever they call it these days). The other companies won't disappear but they will be all playing the low price game like netbooks today.