I think it's simply this. The 'feminisation' of men and the 'masculinisation' of women (both of which grew out of the Second World War), coincided with an era of greater social mobility, greater independence, lower birth rates and so forth. Young men and women began to leave the parental home before they were married. Began to move further away than a couple of streets. Began to abandon the codes their parents were raised with. Being away from anxious, watchful mothers and stern, protective fathers gve many a chance to grow and blossom in ways they might never have done otherwise. But it also left others vulnerable in ways they wouldn't have been before.

It's important to notice the trees, of course, but it's equally important to be aware of the forest!