It seems to me that people have a preference against defection when they are able to grasp that it is in fact a PD scenario. This creates a lower bound on how complex a scenario has to be before people will be confused enough to defect reliably and not either notice or be able to come up with reasonable safeguards. As we create more robust complex things I would naively expect the problem to get worse, but OTOH we have the countervailing trend of coordination and information dissemination getting easier. So...we should want to live in a world where we take it more seriously when economists point out perverse incentives? That starts getting political since many economists have policy axes to grind.