They helped each other rise, and fell victim to their own popularity.
It's not as scary as an AT&T-T-Mobile tie-up, but in the wireless industry, four majors is better than three.
BlackBerry is the latest company to be destroyed by the rapid pace of smartphone innovation. But major wireless providers don't have to worry about suffering a similar fate.
AT&T wants to acquire a smaller competitor. Some experts say that could harm consumers.