I made this point under another parent: $300k includes opportunity cost. Adding four years' salary (even with only a high school diploma) to four years' $40k tuition and living expenses, $300k doesn't seem so farfetched.
Of course, that definition of opportunity cost neglects the pleasures (both intellectual and hedonistic) of spending four years on a campus rather than a job site.
Most colleges do not have $40k in tuition, and most people would not be able to make $50k at eighteen years old without a college degree. That's my point. The actual average cost of college is probably overstated by a factor of two.
Of course, that definition of opportunity cost neglects the pleasures (both intellectual and hedonistic) of spending four years on a campus rather than a job site.