The data has been gathering for years that show the GRE doesn’t do what it claims to: predict success in grad school. (
E.g., Miller, C. and Stassun, K. 2014. A test that fails. Nature 510: 303-304.)
Inertia is hard to overcome. Institutions often don’t want to be the first to move. It’s hard to underestimate how strong the, “Our program has lots of students, so why change it? It’s the industry standard” mentality is among faculty. (I say this as one of them.)
But once some universities started not requiring the GRE, others that do require it are now at a competitive disadvantage. If students don’t want to invest the time and money in writing the GRE, and there are universities that they want to go to that don’t require it, why even apply to institutions that do require the GRE? So dropping the GRE starts to snowball. The more institutions drop it, the more will drop it in the future.
Reference:
https://www.quora.com/Why-are-many-universities-quitting-the-GRE-now
