You're going to have a rough time convincing future employers that you can bring in business.
I can't bring in business because I stay at home with my girlfriend during the weekends instead of going out to the bars? Huh? When I reference being socially awkward that is in regards to the college bar scene.
Go to a different school?
In all seriousness though... There are people who never go out in our class. They are also the ones that look most lonely around the law school building. There are also people that don't love to go out, but do so once in a while (especially at the beginning) to meet people in a social setting. There are a handful of people in our class that don't drink and still go to the bar. It's cheap (most bars have no cover except home games) and it really isn't the animal house atmosphere that you may imagine. Especially with bars like TCB (pool hall), Joe's (more grad students), and Blue Moose/The Mill (live music), you can find a place that fits your personality.
Then, of course, there's those of us that show up to a 10:30am class 10 minutes late wearing a ball cap and sunglasses. But check in with me when grades come out before we decide for sure how bad that does for me.
Social skills are going to be more useful for getting a job than for getting good grades. Yeah, you may get an outline, or a study group, or yadda yadda, but it's just as possible to get good grades without any help from anyone else. A job, on the other hand, is close to IMPOSSIBLE to get if you don't know how to be social. And beyond that... Getting promoted in a legal environment will have a lot to do with your social skills, which probably will include going to bars with your coworkers/superiors, even if you don't drink.
As far as interviewing goes, that is another story. I can be social and interact with employers and coworkers. Unless OCI's are held at 1 AM in a bar, they shouldn't be a problem. In fact, I'm great at interacting with others in an an academic or professional setting. It is just things like parties and bars that I have never felt comfortable in or been a big fan of. Your point about getting promoted once in a job, however, is a very good point. I don't see my decision not to go to bars as negatively impacting my job search, but I could see it being an issue once in a job. I'll have to work on that. Maybe Iowa will be the place to do it!