IIRC, the 2018 Final Four (Villanova, Michigan, Kansas, Loyola) was the lowest rated three game weekend in the past 50 years, with the Nova-UM title game being the lowest rated title game ever., but Villanova-Oklahoma, a couple years earlier, in the Final Four is the single lowest Final 4 game.
I think maybe the powers that be at CBS are happy whenever Villanova isn't involved.