I think you're being too harsh. Lots of marginal students are encouraged to go to college and many of them study things like history or communications that aren't good investments. These marginal students drop out at high rates, but still have 10s of thousands of dollars in student debt. Because most of the benefits of going to college only occur if you actually graduate with a degree it's a waste for these students to spend 2 to 3 years in school where they aren't learning anything relevant to their future employment.