All Things Digital's John Paczkowski wrote that AT&T's service "must be getting better," based on folks raising their hands at the event when asked if they are satisfied with the service on their AT&T iPhones.

AT&T is theoretically doubling the speed of its network, Stephenson said. The speed increase won't help current phone owners, but future phones will be built to take advantage of the improved speed.

The company made a good bet, Stephenson told Mossberg, that the industry was headed toward wider use of smartphones. It's now seeing a dramatic uptakes in usage, so the pricing model must change, he said, without explaining how. In the meantime, he said, the economics of the iPhone are good for AT&T.

Mossberg asked him if he ever asked Apple CEO Steve Jobs to put a keyboard on the iPhone? Stephenson said no.

"If Steve wants to put a keyboard on the iPhone," Stephenson said. "I'm sure he will."

Anthony Massucci is a senior writer for DailyFinance. You may follow him on Twitter at hianthony.