Counting subscribers, T-Mobile + Sprint is still in third place behind Verizon and AT&T. If the landscape wasn't competitive in 2011, then why were there no ef

Counting subscribers, T-Mobile + Sprint is still in third place behind Verizon and AT&T. If the landscape wasn't competitive in 2011, then why were there no efforts by the administration to break up the duopoly? It seems if you want competition, and you don't want a real third competitor, the answer is breaking up the big two. Why wasn't that a thing? It's almost like the duopoly was concern trolling about competition to block competition to their duopoly.