This the very reason that I discussed on the Princeton Thread.
There are many Greeks out in the real world after college and they know that being a Greek brings a lot more information, growing because of interaction than just being a Student.
Networking is not only just between Individual Organizations, but all of us no matter what affiliation.
Do you know members of other Greek Organizations and feel a little closer to them for being Greek?
As munchkin said, a good school name helps, but if you do not have interacting skills then where do you go if you become a blob?