Time will tell. I'm pretty sure it will though. iPhone is 1 device on 1 network, Android will be dozens of devices across almost all networks. It's Mac vs. Windows all over again.
"Gartner Q3 2008 data shows iPhone passes Windows Mobile": http://blogs.zdnet.com/cell-phones/?p=354
Whilst I understand that you're referring to North America you should consider that the iPhone is sold in a lot of other countries.
Although, that's not necessarily a bad assumption, given Apple's attitude thus far. I'm going to take a wait-and-see approach on this one.