They do this already. Adjuncts are teaching faculty. Tenure usually comes with a research expectation and faculty in the tenure system typically have a reduced

They do this already. Adjuncts are teaching faculty. Tenure usually comes with a research expectation and faculty in the tenure system typically have a reduced course load. If a research active faculty member wants to teach even less, then they use grant money to buy themselves releases. Typically even research faculty are expected to teach at least one course as are leadership faculty like deans. Though obviously the provost and president are unlikely to teach but rather raise a shit ton of philanthropy. For context, I have work and consulted for more than a decade at R1 universities that you have heard of.