What is interesting is how alcohol is often seen as part of "college life" but that's exactly the period of your life when you shouldn't be drinking much at all to be able to think clearly.
You, like many others mistakenly believe that the point of college is to get an education. In my estimation (as someone who has been involved with hiring for many different positions) A College degree (even from prestigious schools) is a poor indicator of intelligence, or ability. People who are capable, will learn from whatever source is available (And google is a much better source than all but a handful of professors). People who are not capable of learning on their own *must* go to a university to get an education, but these people make lousy employees, as they can never handle anything outside of the ordinary, and consequently are no better than ditch-diggers. Even the best schools in the world cant teach independent thinking. By the time a person gets to college, they either have it or they never will.
You show me someone who graduated school while attending less than half their classes, and I'll show you someone who will be successful at whatever you give them to do. (This goes double for B.S. degrees).
College is 100% about networking and creating relationships (both personal and professional). To that end, college social activities (including drinking) are an invaluable part of the experience. After all, its not about what you know, its about who you know.
Social interaction is important as is the education aspect, but not even close to 100%, more like 25% (learning people skills), unless you are going to a really good college. One could argue that it's more important in Ivy league schools simply because the vast majority of people who get into Harvard, Yale, etc. are already smart enough and/or rich enough to get a job. The rest is just getting to know people who can help them with their ambitions. However, social interaction itself in other universities is not enough to get your career started.
Yes, if you happen to know Joe or, more likely, his Dad, who works at ABC company and he puts a good word in for you, they are more likely to interview you. However, if you don't have the skills that they are looking for or if you barely passed compared to another graduate that is being interviewed, they are going to dump your ass just as quickly as if you were a nobody.
Over time, once you have job experience, the people that you know becomes more important as they can help advance your career and keep you informed of openings.