I think a part of the issue is we don't have a frontier and the Federal government keeps these people in too much of a check to really get it out of their system. So they hit 25... and it's all over from there, especially if they are lucky and get a few big enough paychecks to do drugs/guns and online radicalization..
We need to designate a few states as a no-mans-land, and build a giant wall around them, and shove these people in there. - we would but like Wyoming has a lot of natural resources. So it would cost money and cause us to have to go through a warzone for our copper tubings. Also the people in Wyoming don't really want these fools.
I think they would eventually develop a unique and interesting civilization however. Something cool. These people aren't dumb. Or incapable. They got a lot of energy, and will, it's just left misdirected and usurped.
They are just frustrated, left behind, abused, full of testosterone, virgins, etc, not that they deserve to get laid, they deserve to be virgins in the giant moonsized penal colony we should build tho. So they can work it out and turn each other into waifus.
They really could become good people. They even have the potential to fulfil their dreams of being guardians and protectors, but they aren't nurtured properly into this role and compensated.