That does beg an interesting thought experiment though: what would that school look like if everything had to be done by the students. Less professoring and upper managerial responsibilities? Make the business students hash out contracts with vendors, IT students handle the networking, mechanical engineers the boilers, hospitality management majors dorm maintenance, and so on and so forth. Something like 15-20 hrs/week, plus 20-30 over the summer from every student is a lot of manpower. Albeit very ill trained/inexperienced manpower.

That said University's don't exactly make an external product to sell, so some money would need to flow inwards from grants or otherwise for salaries and capital expenditure.