That is pretty much what Vance Packard’s 1959 book The Status Seekers describes HYP as: colleges that were mainly for the upper class kids from prep schools (then more SES-elite rather than academically elite) with some actual academically elite kids from anywhere, with only the latter really striving to do better than C or passing work (and being looked down upon for trying harder).
Of course, things have changed since then, so even those who mostly inherited their status feel that they need at least a veneer of their own achievement, and HYPetc. have eventually gotten competitive enough that even the scions of wealth (e.g. legacies) face fierce competition on the academic front (though their prep schools now oblige to maximize the opportunities for such), even if it is a little less fierce than what the unhooked face.