The lack of a degree often became a stumbling point mid-career: People without degrees often wouldn't be trusted for mid-level management jobs. Now if you're a solo act or working for a small company that isn't an issue -- but in a larger company (you know the ones with benefits!) it becomes a dead end.
In fact I'm ashamed to admit it but I now feel at a disadvantage because I lack a postgrad degree; and what makes that depressing is that I'm a creative professional which should in theory be as "hands on" as you get in a career. I also had to say that I've watched folks with ivy university degrees have doors open to them which are often closed to others (look at the last four Presidents of the United States).
Another thing for techies to think about is the fact that there's a ton of ageism in tech that nobody talks about. So yes if you're a twentysomething who can program you don't have to worry, but twenty years later even if you keep up you may not get hired. And at that point having a college degree can open up doors that might have been closed.
But you say that you're the next Zuck: Well one should also keep in mind is that the natural state of startups is to fail. So even if you're brilliant, your company may still fail. In fact even if your company does well there's nothing that says that it can't go south after a few years. And if that is the case having a degree won't hurt you.
Lastly I'd leave everyone with this thought: The value of an education isn't a career unless you are studying business. The value of an education should be to make you a better and more rounded person. And knowing more about the world will make you better at everything that you touch. If you want an example think about Steve Jobs learning about typography in college and how it shaped the original Mac.