I think the point also is being missed that Admissions is generally under the Provost (it certainly is at my top-20). At my institution, the Provost has direct authority over admissions criteria. In addition, our Dean of Admissions actually has a faculty appointment and regularly teaches. I’ve never heard complaints about under-prepared students with the exception of the usual complaints about student athletes (generally from faculty who don’t actually teach them) and possibly a few students admitted through special programs (generally low SES kids from inner-city schools, who do receive extra support).
In some cases, I think our faculty would put additional emphasis on some of the holistic criteria that the OP thinks they would ignore. They certainly would not support reliance purely on stats (since they trust neither standardized tests or high school rigor).