This week proves we’re better off with four wireless carriers

[Commentary] There's a clear case for having more wireless companies rather than fewer of them, and this week demonstrates why.

AT&T unveiled a new service plan called Sponsored Data, which allows companies to subsidize the data being used by smartphone subscribers. While the program means more data in your monthly allotment for you to use as you wish, critics say it creates an uneven playing field for content providers who may simply pass on the extra costs of sponsorship to you anyway. In a monopoly situation, this would be pretty bad; consumers wouldn't have anywhere else to go. It doesn't get much better in a hypothetical duopoly, either. Verizon, the nation's second-largest carrier, hasn't announced anything in response to Sponsored Data, and it's unclear how it would react if it and AT&T were the only two carriers in America. But barely a day after Sponsored Data was unveiled, Sprint has launched its own rate schedule meant to drive down costs for subscribers. And T-Mobile is expected to publicize a plan to start covering the early termination fees of new subscribers.

All of this could happen in a consolidated wireless industry. But it'd be a lot less likely. And as long as having four national carriers can produce these kinds of changes, regulators might want to think twice before smiling on any plan that reduces the field to three.