Markets can not change the fact that humans are not rational, no matter what assumptions people like to make about that. Game theory is littered with examples where the rational behaviour is X, but where humans largely favour decision Y because X rubs us the wrong way in some way or other. E.g. humans are in some cases perfectly content to put our lives at risk out of sheer stubbornness if someone has annoyed us enough - accounting for that in systems aiming for perfection is at best incredibly hard, but far more likely pretty much impossible. You won't see perfect markets. There is no "yet".
I don't think this is about human rationality, or a lack thereof. It's a about whether individual rationality leads to group rationality. Whether the interest of the individual is also the interest of the group. This story is a good example: https://www.youtube.com/watch?v=sb5hr-f3Tfg#t=95
