- There are 13 million iPhone owners
- iPhone owners have downloaded 500,000,000 applications
- To reach a half-billion smartphone applications dowloaded on non-iPhone smartphones, you need an installed base of 1.1 billion users
- Because there are only a quarter-billion non-iPhone smartphone users in the US, there is no way to replicate the sales footprint of the iPhone user base within the United States
The fact Apple isn't the dominant platform for desktops may matter less and less as handhelds are tasked with doing more and more. The future will certainly be interesting.