No, not ALL young people but I would say there are quite a few. Much more then when we were growing up.
I don't think that's true.
I very clearly remember the "older generation" wailing about how the "younger generation" was turning out back when I was growing up. Remember, all those "hippies" with their long hair and you couldn't tell who was a guy or who was a girl (which was strange, because I could always tell who was a guy

), and the beads and the drugs and they were losing their way and so on and so forth.
The difference was, while we were growing up we were much more aware of how our peers behaved, mainly because we were around them all the time (at school and afterwards). The adults were only seeing us/them sporadically, and it was only when their attention was jerked to awareness by one or two of us being rude or misbehaving that they (the adults) took notice of us.
So, we were being judged by the actions of a small minority.
Just the same as the kids are being judged today.
I see a lot of kids while I'm at the store. Some of them are jerks. Some are wonderful. Most are just trying to fly under the radar, same as in our generation, staying out of trouble and unnoticed.
BTW, I regularly say "sir" and "ma'am" to the customers, regardless of age. It startles the kids, sometimes, and then they kinda go "OK," and smile. Terms of respect are terms of respect. They just aren't expected all the time.