Yeah, I think there has been a huge problem with kids/teens/adults being disadvantaged developmentally due to a number of changes in parenting culture. It's more MC kids I agree - I read a study a year or so ago comparing MC and WC kids and not surprisingly, the MC kids had advantages in terms of school, skills like music or access to sports etc. But the WC kids were more independent and took initiative. It's really influenced how I've tried to treat my teens.
As far as the things that are causing the problems, I agree lack of boundaries, but at the same time, lack of freedom. No one really tells them "no" much, even many schools are pretty lax, but on the other hand there is no going outside in the neighbourhood all say away from parental eyes. Even families being smaller has an effect, when you have more siblings you can hide in the group a bit more. Kids have a strong tendency to bring each other down to reality pretty quickly. That can allow bullying to happen but it's also where kids learn a lot of social realities.
Always being supervised also means that kids don't have much chance to problem solve alone, maybe even when they feel intimidated or scared. I remember getting lost as a kid, my sister falling off her bike, trying to figure out how to get getting to totally the wrong part of town when I was 14 on the bus... I think this starts even younger though.
Parents with little expectation kids should work and be contributing to the work of the family. I wouldn't make a huge distinction there between home work and paid work, either, though some jobs clearly aren't appropriate for some age groups. There was a thread in AIBU the other day where a mom was asking if her 10 year old child was unusual in really refusing to help (and be paid) for helping out stuffing envelopes etc for 10 to 20 min a week in the family business. I think everyone agreed that was not unusual for that age, but what surprised me was how many said asking a child to do that was abusive and they would call social services!
I think there is a kind of learned helplessness a lot of kids have now - they get used to being taken care of, not contributing materially to the family, the "tribe". Most kids are developmentally ready and often eager by the early teens to contribute and be independent, in a traditional setting they would have been entering adult life by the early teens. But modern life means they can't, and it almost seems like if you miss that window, they have grown used to being maintained through the work of others. The transition to maintain themselves, much less anyone else, is more difficult.