Both are true.
When I was 18 I use to earn around $200-220 a day as a site operative on building sites doing Aircon installation. This is because you have to really put in the grunt work-the old iron cylinders are not light. They use to take most the kids from care like myself for these jobs because we usually work out from far too young an age.
However, now I earn a little bit more than that as a Corporate Coach and considering I am 27 that is because of my Msc from LSE in UK.
So it is a double-edged sword. You are what you put in. College is NOT the guaranteed meal ticket it was 20-30 years ago.