I went to school in NYC and lived there for years. I found that there was a lot of cross pollination among the schools. Frankly I don’t know how anyone who has not been a student in all of these cities could possibly know how unique Boston is or isn’t.
And I don’t know what difference any of this supposed interaction would make anyway. Students are spending 95-99% of their time on their own campus, not running around interacting with students from other campuses.