I just want to point out: At the time of the iPhone launch, AT&T's business model (and every other telecom up until this tipping point) was to sell "minutes" which was essentially micro-charges for consumers who want to make calls or send texts.

This was mostly an infrastructure problem that Apple innovated on and helped AT&T solve- carriers would no longer need to sell "minutes" but could instead sell Data, which was a much better value proposition. There's a quote in the movie Blackberry along the lines of "the problem with selling minutes is that there's only 60 of them in a minute to sell".

I can only assume this attributed to the global adoption of the "data sale" model (and the iPhone with it) since the profit ceiling was exponentially higher for every carrier.