I confess I haven't read all 17 pages yet. But a few thoughts as I read.....
I think feeling useful and needed is more important that just being given jobs to do to keep busy. In the 1700's and until recently every child contributed to the family in a meaningful way. If a job didn't get done it could mean not eating or something equally important to the family's survival. Most of us no longer have that type of situation.
For young males I am a HUGE proponent of scouts. They learn useful life skills which can mean the difference between comfort and logical consequences.
As for adult children leaving home as a sign of maturity, I am not so sure. Most families had lots of land and the adult children settled on family land and worked in family created industry. Children lived at home until they married. Another dynamic that is hard to recreate.
Sadly not all of our children are going to be the Jeffersons, Adams, or Washington's. Some of them will carry their bags. Just like there were men of thier times then, there will be men and women of the times now.