When a person weighs the positives and negatives of speaking out, and the system is set up in such a way as to almost guarantee no positive outcome, then why would anyone speak up? Personal ethics come to mind, but you can't eat personal ethics or pay the rent with it either. Plus, conflict is stressful.
I think about this often. Is my personal involvement as an employee in a nationally corrupt system (for profit healthcare) mean that I am making an unethical decision each time I show up for a shift?