I think more what has changed is that the intervening bystander doesn't just take on the danger of the situation but the risk of societal condemnation and serious legal ramifications as well. Added together fewer people are going to get involved unless it is someone connected to themselves. A sad state of affairs but I think we need to acknowledge it is not the individual "men" who are reluctant to act who are at fault but society that has made the potential cost of acting too high. The Penny/Neely case reinforces this fact even though Penny was acquitted.