Momentum that even Google has no control over, and it likely to pull the platform apart into multiple branches (fragmentation). Just look at what Amazon has planned for their new 7" tablet for example, it will be hardly recognisable as Android. They are stripping out all of the Google services and branding. As another example, look at what Baidu are planning to do with Android in China. Again, a completely different branch of Android is forming, it's like desktop Linux all over again (and we all remember how well that went when it came to dislodging Windows).
It you had said that iOS had won, I would have thought fair enough (as much as it pains me that iOS currently represents the future of mobile computing), but Android? Really?