Not just a lack of discipline in the school system. There was no school discipline back in my day, when the "ments" were setting kids' hair on fire on the bus. But apparently they, like everyone else, hadn't even imagined BJs on the bus.
If you had been on the bus, and some guy pushed a girl's head in his lap, that bus would have stopped and both participants (if she was willing) would have been warned by the bus driver, or maybe even kicked off if it was not the first offense.
This has obviously been let to get out of hand. If people had been disciplined (i.e. refused bus privilages or been suspended), this could have been taken care of. The change is not in man's capacity to act immorally, it is in our reluctance to enforce discipline.
You cannot legislate morality, but you can punish unacceptable behavior.