More can be said if anyone has anything to add (especially with regard to different decades*), but in the meantime you may enjoy this older answer:

• 1960s: Could a white male 18-year-old American really get a union factory job with good benefits just by more-or-less showing up at the factory in a suit with his HS diploma in hand? by /u/BigBennP.

^(*Boomers turned 18 between 1964 and 1982, so of course this answer only accounts for some of them.)