Okay. I'm probably a good bit older than most folk on this thread, but I just need to interject that there's a vast difference between the working class and the underclass.
Even when I was a child in the '60s there were some families where no one had ever done an honest day's work. (Though the men had been in and out of prison.)
Those of us who had fathers who actually worked for a living - mine was a coalminer - did not approve of that type of lifestyle and the underclass was certainly in the minority.
I'd say that they still are - it's just they we hear more of them these days.
So far as the behaviour of teenage boys is concerned, I'm afraid that - based on my experiences as a secondary school teacher - I've seen a deterioration in the middle class boys as well.
You'd see families where the girls were working their socks off, but the boys were lazy little sods who would airily inform teaching staff that they didn't need to pass exams since they'd be inheriting daddy's business and grandad's house.
To be fair, there were also some feral middle class girls, but not quite so many. By the time i quit teaching, you'd see girls who refused to come to school until they'd donned a full face of evening style make-up and who had the notion that all they had to do was to marry well or "be famous".
The most vicious girl that I ever had the misfortune to encounter was a solicitor's daughter.