Why is Rush so Cut-throat on the Sororities' End at Big Greek Schools?

[KillarneyRose]

It seems that rush competition between the sororities at schools that have strong Greek systems (LSU, UF, Alabama come to mind, among others) is unbelievably cut-throat.

Often, so many young women rush that a couple hundred of them don't receive bids. From what I understand, even legacies and women with multiple recs get cut. So it doesn't make sense to me that the sororities fight each other so hard when there are plenty of rushees to go around.

Could someone who's "been there" or is otherwise knowledgable about the process maybe try and explain a bit? I'm very interested in this because it is so foreign from my college experience at a place with a small greek system!

Thanks