Your memory's off. Leary beat Collins out in 2015 TC just like I predicted he would and started the season until a groin injury cost him his job and even then only after several games.
Basically Leary got Romo'd. Collins never outplayed him but took over while Leary recovered. Younger (slightly), more highly pedigreed, and with no looming knee condition he better represented the future to Dallas so they stuck with him.
Leary wasn't given reps to compete after that.
I loved watching Collins reach the second level, but he wasn't as good or nearly as consistent at blocking the first level as Leary. Especially in week 1 when he and Free shat the bed.
What has been idiotic is their refusal to develop Collins as a RT. He's just a better fit there. At 6'3" and compact, Leary's a born guard. Collins is 6'5", athletic with long arms. He needs to be out on the edge.
PFF grades from 2015:
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