Actually I think it has more to do with the isolation of generations than with schools. Kids nowadays (just saying that makes me feel like someone's great aunt) have had much less contact with other age groups than any other generations. They know a great many kids within 2 years of their own age and a few career age adults including teachers and parents. As a result they don't hear the expressions and aphorisms and stories that used to be passed down in conversation. The generation that are parents now were almost as segregated so aren't able to pass them on, even if there was the level of conversation as recreation that it would require. Having videos even in the back seat of the car isn't going to help either.
I read of an inner school project in London to reduce shcoolyard violence. The teachers realized that the kids were so segragated by age that they didn't learn the traditional schoolyard games from the older kids. When the teachers took turns teaching marbles, skipping games, hopscotch etc bullying and fights dropped dramatically as the kids now were active instead of bored.
