I think the school systems are better now than they were in the past as well.
What most people do is they look at the kids and how bad they are and blame it on the school system when in fact it would be the decline of the traditional american family that is more of a cause than anything else.
I also can see where a motivation factor might kick in with teachers as well. Tell me why they should try harder to teach these bad kids whos parents do not care enough about them to teach them to respect other people? The teachers get paid the same one way or the other. If you are a great teacher you get paid the same as a good teacher and you get paid the same as a bad teacher. They all get the salary based on years of experience which eventually makes them work just hard enough not to get fired. Now this is not all of them but I can see it happening easily.
Tell me if you knew the guy down the hall was doing nothing and getting paid the same as you and you were working you butt off that that would not upset you. It would. Of course in our jobs the guy down the hall would be fired even if it takes a few years to do it and you would keep your job or even get promoted because you work hard and do good work.