Few teens any more are given sufficient responsibility to teach them what it is. They don't even accept responsibility for their own actions, let alone for future duties. One result is the "It won't happen to me!" syndrome.
Excessive free time needs curtailed considerably, and responsibility is one way to accomplish that. A teen with a job (learning job skills as well as responsibility) doesn't have time for partying to anywhere the same extent. A hundred years ago a 15 year old was nearly adult, working to support himself - today he is a party animal with nothing but time to burn and hasn't a clue how the world works. The work load of the past is no longer necessary nor desirable, but some of that work load needs to remain.