Ultimately, there's no one to blame the protracted demise of the "Greek" system on but the "Greeks" themselves. My own school, Wesleyan University, has changed its mind from forcing fraternities to co-educate to just kicking them off campus.
The news that the Kappa Delta Rho fraternity at Penn State had allegedly run secret Facebook pages where they posted images of nude, unconscious women should have come as a surprise. But given the numerous incidents of fraternity misconduct in recent months, it didn't.
What separates Greek culture from the rest of the student population is that we are an organized institution. What happens within our purview reflects directly on us, rather than just on those involved, as it is for non-Greek students.
Even if fraternities aren't directly responsible for every instance of sexual assault and inebriated death on a college campus, they engender an attitude that is no longer permissible in the 21st century.