A big part of it is having a long-term peer group of people who were disciplined and motivated enough to get into MIT and succeed there. Arguably true for any university. We're products of our environments, and if you surround yourselves with hardworking people it rubs off on you.

On the other hand, many people act like "talking to professors over beer" (or to your classmates, for that matter) is supposed to add "value" to the college experience, when it's perfectly possible to get at least a bachelor's and a master's without ever doing that (source: I did).

Two people with the same GPA and same piece of paper from the same college, may have gotten different amounts of lasting value from their college experience.