Some businesses extract value from an employee based on how impressive-seeming that person is on paper. This happens a lot in consulting, finance, law, arts, academia, corporate business administration and politics. In these domains, status and affiliation are very important, generally vastly more important than actual productivity. Since these fields are also associated with things like wealth, elite status, access to private clubs and opportunities, being a sought after relationship partner, etc., it glamorizes them and by extension glamorizes the path necessary to get to them -- typically either happening to come from a well-connected family or else attending an "elite" school and succeeding in networking there.
Effects like this snowball. So once a school is known for producing graduates that others are desperate to affiliate with in a certain field, like say art or law, then impressive people from other fields may be drawn to work there, like an excellent professor of computer science who thereby actually does elevate the level of education granted to computer science graduates, making graduates into the sorts of people that tech companies want to get on-paper for acqui-hires because acquirers will want to affiliate with them.
One general trend I see in humanity is that the more that we advance a sort of scientific and rational understanding of the world -- something that should supplant most of these systems of credential -- the more that human politics is used to build Dutch book-like circumstances in which, no matter what the outcome, impressive-seeming-ness and competition to affiliate with "fancy" people will continue to be the dominant manner of achieving wealth and autonomy.
To be clear, even though I attended an Ivy school, I find this lamentable. I did not enjoy my time there and feel basically how Mike Reiss feels. But at the same time, I also see all the banter on Hacker News about how the degree doesn't matter and I just roll my eyes. What is it that people think? That something like HackerRank or TripleByte are going to democratize tech hiring? Please. They will be (and already are being) used as just additional tools in the political toolbox to allow people to make up whatever arbitrary standards they desire for the sake of favoring candidates based on political reasons.