My impression is that problems with Greek systems have become worse nationwide, for whatever reason. Just in PA, the recent drinking-related fatalities at Penn State and Lafayette got a lot of coverage. Do you really think that Lehigh is different from other small universities in the northeast, like Dartmouth or Bucknell?
Well, Lehigh already requires freshman and sophomores to live in campus housing, and they have just broken ground on a large new dorm. But that dorm has probably been in the planning stages for years. It would take decades them to provide campus housing for everybody.
My preferred answer would be to lower the legal drinking age, at least in designated areas on campus. When I was an undergraduate (which was not recently), my college operated its own pub. Students of any age (but not outsiders) could freely go there to socialize with drinks and learn about the effects of alcohol in a well-lit, public, monitored environment, then stagger back to their dorm rooms (without driving).
In other words, there is going to be underage drinking regardless, so let’s allow it to happen in a safe, aboveground manner, instead of driving it underground into fraternity basements. Unfortunately, this would be totally illegal under current laws. So my answer is as impractical as yours.
South Bethlehem is your idea of “drug and gang infested”? Good thing you don’t go to a school in a place like Baltimore (Johns Hopkins), New Haven (Yale), Chicago (U of C), or South Central LA (USC).