At the more desirable schools, tuition fees don't pay for tuition costs either. There's a correlation between how much the college (and its donors) give to a student and the quality of the college, for reasons that are obvious upon reflection: it aligns incentives. If the school is paying for your attendance, their motive is for you to succeed at something (or else why would they bother schooling you)? If the school is profiting from your enrollment, their motivation is for you to enroll, not suceed.

> Most universities primary function is research

Actually, in the US, at the vast majority of universities, the primary job of faculty involves teaching, extension/outreach, and forms of service like mentoring students. Most universities have research expectations, but that is not how faculty spend their time.

> and tuition doesn't pay for research.

This is a STEM-oriented view. In a lot of fields the primary cost of research is faculty time, and it is often paid by tuition.

>This is a STEM-oriented view. In a lot of fields the primary cost of research is faculty time, and it is often paid by tuition.

While I don't doubt there are colleges out there that primarily function of tuition, I'm fairly confident that the schools that the GP was talking about which take in millions of donations, are not funded by tuition - STEM or not. Endowments are practically tax-free hedgefunds. There are several liberal arts colleges in boston with billion+ endowments - where the return alone on the endowment rivals the total revenue from students (assuming they were all paying the full 50k, which they likely aren't).

Per my anecdata, it wasn't a research university, just a liberal arts college. From what I can remember, most of the donated funds that my extended family gave went to scholarships, though I'm not 100% on that.