Ross Rubin, directory of industry analysis at market research firm the NPD Group, agrees. "If you wanted an iPhone or other handsets in AT&T's portfolio, you had that option today--you could've switched and paid more, potentially, for your data plan." While Rubin thinks some may want an iPhone, he also suggests that other value carriers like Cricket and Virgin Mobile may be better positioned to grab T-Mobile customers.

Michael Gartenberg, an analyst with technology research company Gartner, said that AT&T and Apple can't be assured that T-Mobile customers will follow their phone company, no matter the lure of the iPhone. "The big challenge," said Gartenberg, "is that people want T-Mobile for a reason, they were with T-Mobile for a reason. You probably want to be convinced that AT&T gives you the same value as before, and if not, that opens things up. The consumers are in play."

Apple seems certain to pick up at least some gains from the expanded carrier and, between the new AT&T and Verizon, the company seems poised to make the iPhone available to the vast majority of American consumers.

Added Gartenberg, "If those T-Mobile customers flock to AT&T, that's probably a good thing for Apple."