According to Horace Dediu of Asymco, Google's smartphone revenue per year is on the rise. On the surface, this appears to be good news for Android, but a closer look at the source of the revenue shows that most of this increase is from iOS. In fact, Deidu suggests revenue per device from Android is slightly declining. If you are wondering, Google is making money because of its prime placement as the default search engine on the iPhone and iPad.
Dediu also notes that though the Android platform is sustainable from an economic point of view, Google is only getting US$1.70 annually per device, while Apple is making over $576 per iPhone sold.
You can read his post on Asymco's website and comment on his analysis.