Kids will be kids regardless of what you do to stop them. I know most campuses are moving away from this kind of system. I went to school in Arizona and I can tell you that they were out of control, when I went there. It was a crazy time either way though.
Yes, fraternities and sororities are the biggest reasons for drug and alcohol problems on campus, because most of the Greek organizations just look the other way when there is drinking on campus. Frat parties give people a place to go and drink. It is not as much fun in your dorm room all alone.
I think that the reason there are a lot of drug and alcohol problems on campus in universities and colleges are due to the fact that it is filled with a lot of young people who are experiencing freedom for the first time. While frats and sororities don't help the situation, they're not the reason for it.
I do not believe fraternities and sororities are the biggest reasons for drug and alcohol problems on a campus. I believe colleges create this problem by trying to restrict adults from doing as they please. You can't eliminate things like this from a society, so why bother trying? It only causes more problems.