University research is labor. Researchers get salary or stipend, usually relatively modest on the ridiculous white collar standards. Nobody gets rich from grants. Typical best case scenario for grant researchers is to stay employed. Tenured faculty don't get any money from the grants.

(Very) few do get rich by leeching publicly funded research for spin-off companies. High level admins can get relatively rich from obscene salaries, but they aren't the ones applying for the grants or doing the research.

Probably not altruistic, but not usually primarily for money either. If money is what you want, university is a very bad place for trying to get it. People do do things for other reasons than economic gain regardless of what the prevailing economics dogma and ideology claims.