Who do you think advises students getting into classes, who do you think reviews applications or works with companies to get students jobs. There is administrative over head because these activities are not core competencies of researchers.

People act like a reseach faculty member should be conducting cutting edge research while writing findings applying from Grant's advising students on course course offerings and courting employers while also snoozing with alumni for donations.

Noone can do it all and thus there are specialist in these fields that usually cost a fraction of what a faculty member costs.