My comment was really more about brain development, maturity, puberty (and the hormones that go with it), and things like that. It doesn't mean they are lazy or anything like that at all. These things are learned, and these young people aren't even in high school.
"mostly letting them do what they want" isn't true now and I don't think that has ever been true. As far as what to do next, we can start by trying to make sure folks have stable households which include not only things like shelter, food, and medical care but also things like internet access. These things lessen the stresses that are an issue - being poor won't necessarily make you suffer.
Make sure kids have freedom to explore. Treat kids like they are intelligent (they are, just not mature) and teach what sort of work goes into getting things. Be realistic about what to expect out of life (for example, a chem degree might really wind up working in a lab somewhere). We could do things like showing kids how work and patience pays off by allowing "fun" subjects (arts, music, inclusive sports, "hobby" classes). Increases in freedoms as kids get older so they can experiment with some of their choices (Such as being able to have free contact with friends, choosing one's own classes, ability to not follow in the parent's religion). A 13 year old might not be mature enough to realise what to do to make their future better 15 years into the future, but these sorts of lessons can be taught so when the maturity catches up it'll come together.
(I should note that naturally, some kids are geared more towards some of the long-term planning than others and I cannot speak for all young folks, just what I notice).