[valley_guy_12]

Second reason it didn't take off faster was that iPhone was typically a carrier exclusive, and in most markets, the iPhone carrier was typically one of the smaller carriers. So iPhone wasn't available to most mobile phone users in a given market, unless they went to the trouble of switching carriers.

[MBCook]

Plus the App Store was a massive driver of demand, but wasn’t there until year 2 and the release of the 3G.