AT&T was happy to sign up as many iPhone customers as they could. Their mentality was probably very similar to gyms who sign up as many people as they can in January when everyone makes their New Year’s Resolution to lose weight. Gym are packed the first few months after January but then there’s a drop-off in attendance, because people tend to slack off
In fact, far from being New Years’ Resolution Gym people, iPhone users are probably using their iPhones to stream music at the gym. All the more data for AT&T to try and avoid handling.