While according to Harvard itself: "The total 2013-2014 cost of attending Harvard College without financial aid is $38,891 for tuition and $59,950 for tuition, room, board and fees combined."
Unless summer+part time work is a lot more lucrative than I am aware of, the only way this would be true is if the students (or their parents) were financially well-endowed. A student that doesn't have rich parents is going to be incurring a fair amount of debt or spending way too much time working instead of studying.
Edit: Harvard is generous with its financial aid, so the author's message is more accurate than I understood (at least for Harvard). Learned something.