Minig is an iterative prisoners dilemma auction. The rules of iterative PD are different to that of a single auction. Folks, particularly miners, just havent realized this yet, because the subsidy dominates. But it wont long-term. Miners will lose money in the long run, if they prioritize the obviously bad transactions. If you don't believe me or don't get it, I don't have time to try to convince you, sorry.