When Verizon bought Alltel, it became the biggest carrier in the US, with 83.7 million customers. Two years later, it has 94.1 million customers. And as of today, AT&T is number one again, with 95.5 million customers. Why? the iPhone.
Not to put too fine a point on it, but a ton of AT&T's subscriber growth has been the iPhone. This quarter, 20-25 per cent of the iPhones sold were to new customers - so around a million of the 2.8 new customers they added came aboard with the iPhone. (Update: The million new iPhone customers were also offsetting people who left, hence the stat AT&T added only a net of 400,000 post-paid subscribers this quarter. Put another way, as AT&T explained it to me, they had 2.7 million gross sales to new postpaid customers. So nearly 40 per cent of their sales to new postpaid customers were iPhones. They just lost a bunch of postpaid customers as well, hence a net gain of only 400,000 post-paid customers.)
Last quarter, nearly 25 per cent of the 5.2 million iPhone activations were new AT&T customers - 1.3 million, to be precise - which amounts to about half of the 2.6 million subscribers they added. Or a year ago, when AT&T added 2.7 million customers, over a third of the 3.1 million iPhones they activated were new customers - more than a million. You can see it again as you dive back into their earnings and subscriber numbers. (This, in case you are wondering, is why even Verizon, with its Mighty Network, wanted the iPhone so badly.)
AT&T will totally keep making buckets of money selling bushels of phones, even with the iPhone no longer their exclusive baby. But they might not be the biggest carrier in the country for very much longer, so they should enjoy it while it lasts. (This might be why they didn't trumpet it too loudly. Which is to say, not at all.)