Vicious cycle. In some cases jobs like mill or mine work dried up. But also, people who worked hard at physical or technical jobs wanted things to be "easier"for their kids. So the kids went to college instead of military or trade schools (or simply getting similar jobs as their parents). Some took tech or premed or engineering but most gravitated to the softer subjects. Alarming numbers of English, sociology, "popular culture" majors. College admins themselves come from this background so emphasize the BS classes needed to take. Not many actual jobs in private business requiring these majors so government absorbed many of them.
In turn, government magnified the importance of college and provided more opp for grants and "low interest" college loans. More and more kids ( mostly pushed by their parents who had those soft majors themselves) who had drifted through high school (which also had been softened) then drifted into college to major in communications, literature, etc. Colleges loved that, jacked up tuitions, provided more amenities to compete for students etc ... including offering more fruit pie majors.
But even the government couldn't absorb more of those kind of grads, so they're back living in their parents basements (or old rooms).
There are at least 6 houses on my block where exactly this has been the case. Multiple kids went off to college, majored in fun things like Art Therapy (taking 5 or 6 years in some cases), had great times, but now back at home working in retail or Starbucks (at least they are working). Multiple have their girlfriend or boyfriend living with em too! There are 5 cars crowding driveway, street etc that should only ever have two. Parents who had thought they could retiree and downsize are now stuck.
And I'm not judging, I have a kid entering high school, loathes math and science (which seems the attitude encouraged by celebrity culture) and mentions "graphic arts" and "theatre arts"as fields of interest, and I cringe about what we're gonna do.
Meanwhile it took me days to get a plumbing company that could change out my water heater last month. They claim they can't find enough workers.