>Couldn't it be that history books give a sanitized view of society, and gloss over relatively minor issues such as disobedient youths? The books might say, "young people were expected to be x, y, and z", and tactfully omit, "but they were frequently a, b, and c despite our best efforts".

Frequently yes. Kids will be kids. We're talking about societal norms, and those have changed tremendously. Even in your example, the important thing is "young people were expected to be x, y, and z", not if they actually were x,y and z 100%. Why? Because today they cannot even be expected to be x, y and z in the first place. A lot of the past's x, y and z sound unbelievable today in themselves.

Anyway, regarding all this, if people have doubts, try talking to older people, your grandparents if they are still alive.

>Also, the following is commonly attributed to Socrates: "The children now love luxury; they have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise".

That's nothing of the scale you see today. Plus, he was speaking in an Athens that was about to go down the drain, i.e in a society that has lost the "connective social tissue" and people were becoming more selfish and greedy. So, if you see a parallel maybe it's not because it's been like this for 2400, but because we live in a similar era of societal decline. Things do reappear in history, after all.