Frank Mir is a gatekeeper now, he will never beat Overeem, Cain, Carwin or JDS ever. Mir is an amazing fighter, but he is not skilled enough to ever beat any one of the top 4 fighters in the UFC. He has the build and strength, but he's just too far behind the top 4 in terms of mma development, he stagnated for years while Overeem was winning K-1, Junior was becoming an elite striker and Cain was spending countless hours in the gym. Mir takes the sport too casually in comparison to the top guys to do anything, if Mir wanted to be a champ he'd go train with Jackson's camp. He'll make one more push, lose to one of the top 4, have one more gatekeeper fight then have a legends retirement fight (maybe they signed Fedor by that point, I'd watch Mir vs. Fedor).