When I was in high school, there were always posters hanging up showing how average income rises with each level of education attained. Although those were just aggregate statistics, it was always thought of as a guarantee, both by the students and the teachers. But of course, it isn't a guarantee at all.
I ran across this chart today, showing yearly income:
You'll notice that education seems to benefit men a lot more than women. Most of the income difference is simple discrimination (women make somewhere around 75 cents vs. a man's dollar for equivalent work in the US). But part of this has to do with differences in what men and women major in. For instance, women hear that education and health care are the only booming areas of the economy, and they're seen by society as natural care-takers in a way men are not. So they more often major in things like social work, early childhood education, or nursing, which don't pay as well as, say, an MBA. The above chart was created in 2006 from census data; in 2006, 35% of MBA students were women.
You also have to consider that while incomes are higher with a college degree, if you went to a "good" school you might be paying $500/month or $6,000/year in student loan payments for many years after graduation.
And this chart does not take into account that some of the PhD's, for instance, didn't attain this degree until they were around 30, if not older. If you live in a college town you're probably familiar with the long-term graduate student lifestyle. Even if the income is much higher after that dissertation is finally defended and a job is found, it isn't clear that it would make up for 12 years of very low income. And I hear it takes more like 6 years just to get a bachelor's degree these days, not 4. Not that you couldn't do it in 4, but the average amount of time taken to attain a bachelor's has been increasing.
You'll also notice that those with some college are not in much better shape than those with a high school diploma. I think there are a lot of kids who go to college because that's just what's done, in the middle class. Don't think, just do it. But if you don't know what you want to do for a career, you might spend 6 years fiddling around, racking up debts, and never get a degree. Now you have 6 years' lost income and debts to be repaid-- debts which cannot be wiped out by bankruptcy.
It's something people should think about, not just sleepwalk into because hey, they're middle class! Of course they're going straight into college! Some kids may have a career plan that might not include college. One of the smartest and most successful people I've met in recent years was the electrician whose company installed our generator. He also drag-raced cars and told us about a recent race in what seemed to me like another language, and involved a lot of numbers. I don't know for sure that he didn't have a college degree, but he would not have required one to do what he did; his educational path would've involved apprenticeship and certifications.
Many parents, though, are so certain of their children attending college that they've pre-purchased the credit hours at the state university, often many years in advance. Turns out that's probably not a good idea, as the pre-paid plans are being mismanaged in some states, and do not contain actual guarantees in most states.
I imagine my kids will go to college, but I'd like it to be a deliberate, carefully considered choice.