as with most things we don't know the details but i would assume there would be a benefit, There really is no reason for there to be any kind of diminishing returns when it comes to research/learning.
if anything it would make more sense for it to be the other way around where having more of it in one location should give them a cumulative buff and create a reason to have something like an academic city.
and its probably more accurate to think of it as X amount of people rather then X amount of schools.