back when my D was applying to grad schools, I killed some time by searching the bios at at the top 10 schools in her field (per NCR rankings). The results were not surprising at the top end, at least to me. The faculty members earned that Grad degrees from dozens of schools, but hiring/placement is still concentrated on the usual suspects. (Of course, it partly depends on the size of the program at the Uni. If top school x does not have a large grad program in xx field…)
(Grad of tenure track faculty of Top 10 Unis in descending order)
Harvard
Stanford
Michigan
Yale’
UCLA
Cal-Berkeley
Penn
MIT
Princeton
Columbia
Arizona State
Cornell
Besides the possible outlier, ASU (really large program in her field), what I did find surprising was that top schools like Chicago and Emory were way down the list. And sure, while there was a faculty member who did their work at Vermont or UMass, the numbers were like 25-30/1.
Prestige matters in academia.