I don't disagree. But the cost of attendance includes a line item for "personal expenses" (which includes books and all that stuff). For 2019-2020 academic year at Harvard, that line item is $4,193[1]. There's also a line item for "travel expenses", but when using their net price calculator with my circumstances when I went to school, that kept coming back as zero.
By zero'ing out tuition, fees, and room and board, that leaves $4,193 as the cap on demonstrable need, which federal loans and many scholarships will use as a max limit on cumulative aid. This is unrealistically optimistic, and serves to needlessly cap the potential ability to raise funds via merit scholarships or loans, shifting part of the cost burden to ongoing cashflow.
Which, I'll concede, isn't necessarily too hard due to the plethora of work-study and student jobs available. But I only knew that after the fact, and the prospect of getting stuck far away from home without the money to make ends meet and the knowledge that your family is too far away to help you get home and too poor to help financially is terrifying to a kid right out of high school.
I also learned, through the work that I did for the university I went to, that the cost of attendance isn't as black and white as it's made out to be either. Although universities may differ in policies, they can make accommodations in your individual cost of attendance letter if you can justify the deviations. But I only learned of that flexibility after experiencing the system, and it wasn't clear at the outset. So I didn't even realize that was a possibility when evaluating acceptance offers and aid packages.
[1] https://college.harvard.edu/financial-aid/how-aid-works