This. Plus, in the case of Apple, they have a distinct first mover advantage. As we learned from watching the original round of Mac vs. Wintel, in the platform

This. Plus, in the case of Apple, they have a distinct first mover advantage. As we learned from watching the original round of Mac vs. Wintel, in the platform market, first mover advantage accrues to the company that puts together a viable OS + application ecosystem. That's why they're printing money, and it's why Android will have a very difficult time unseating iOS. Android is somewhat behind in the maturity of their OS. They're incredibly behind in the size of their app ecosystem. While I don't see Android ever shrinking to Apple's late 90s market share, I'll be surprised if they ever exceed Apple's installed base. I think most of Android's advantage so far has been in distribution. And now that Apple is free of it's exclusive contract with AT&T, I don't think that Android's advantage will last.