It's been my observation that de-emphasizing the alcohol aspect of Greek life does a couple of things. Students don't drink any less - but they do it in the bars and in the dorm rooms. If schools don't watch out, they'll be forced to confront the truth that drinking isn't a Greek problem, it's a *student* problem.
I think the Greek system may initially shrink a bit as those who are joining it for the keggers stop, and it will take a while before the people who would join for networking/brotherhood/career/self-improvement reasons to realize that Greek life is for them. Eventually I think the system will end up stronger.
Before I graduated, several fraternities went dry at my campus. The results were mixed - the "nerd" house was not impacted but the "lush" house was. I think as more houses go all or partially dry, the remaining ones will have increased risk management problems and pressure to go dry themselves.
As for my org, AXD (like all national sororities) is already dry, and we have some of the toughest rules about things like 3rd party vendors and alcohol at mixers. It would be hard for us to get much more dry.
Except that, as sorority women, we've been getting a free ride off the fraternities for years - we drink at their houses, maybe in their letters, on their dime, including the not-insignificant risk management dime. In actuality the men have been footing the bill for Greek men
and women for years.