There's another cost, some jobs you just won't be able to do when you have a wife, kids, and lots of loans to pay every month. At college age is part of the very short time in your life where you are free from all this and can easily focus on something harder than virtually anyone else.
Of course, the majority of people will never consider even performing at this potential. But could it be different if college as we know it wasn't so severely required?
That's the first cost that came to mind when I read the title. On the other hand, there were some good parties and women.
Shotgun weddings and medical emergencies aside, nobody's going to force anybody to get married, have kids, and take on a heavy debt burden. Screw the Joneses. And this isn't to say you should be a bachelor for life; I'm sure there are women out there who value freedom and a man who's willing to make sacrifices and go his own way in search of that freedom.
I went to a community college paid for entirely by scholarships, so the cost to me as far as money goes was only that of the books. The largest cost to me, though, was the time invested in classes where I learned very little.
Back to money though, my pay jumped $2.75/hr at my day job as a direct result of getting my two associates degrees.