In my generation during High School all the boys got construction jobs because they paid the best. By doing so we all had a serious understanding on how things are put together. I think todays men coming up don't do that because of all the low wage immigrants in construction have killed the high school labor market.
Nope, litigation and government regulation had executed the high school labor market before illegal immigrants became such a huge problem.
I suspect it's because there are so many other, less dirty, jobs out there that high school boys can do, they don't WANT to do construction. They don't see the value in learning the skills.