“The children now love luxury; they have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise. Children are now tyrants, not the servants of their households. They no longer rise when elders enter the room. They contradict their parents, chatter before company, gobble up dainties at the table, cross their legs, and tyrannize their teachers.”
Maybe it is not so universal, but an actual predictor of civilizational decline?
I think it is more of an indicator of overall prosperity, which may, in fact cause civilizational decline. I'm reminded of the mouse utopia[0], and my own family.