Enrollment in four-year colleges was 40% in 2004 for low-income students, down from 54% in 1992, and 53% in 2004 for moderate-income students, down from 59% over the same period
The net price for attending a four-year public college in 2007 for a low-income student was $10,620 - 48% of family income - up from $7,570 - 48% of family income - in 1992. The cost for a moderate-income student increased over the same period to $14,650 - 26% of family income - from $8,790 - 22% of family income.
College costs too much, so poor students aren't going as much. That means they can go out and get a job for four years and start saving, while their richer counterparts spend four years paying extravagant sums in order to earn a diploma that is actually less than worthless for them, financially.
Unless the poor high school grads can't get jobs at all, in which case, revolution. Either way.