Before I started college, I read this professor's speech, which attempted to explain, given your concerns, why an education may nevertheless be valuable. It's biased towards its audience (UChicago students) but I think its relevant point can be summarized as: few jobs allow you to continue practicing the diversity of skills employed by academic work, and having a degree keeps your options wide open for a longer period. However, the real thesis of the speech is that university is uniquely a place to devote oneself to practicing the Art, broadly construed, of generating knowledge and beauty from everything.

Other considerations:

• Becoming an academic is very hard without an undergraduate degree, so if you want that life, stick with it.
• It takes a great deal of luck to pull a Bill Gates. It is otherwise hard to convince people that your reasons for not having a degree are genuine and not ex post.
• At least in my case, it has been hard to find anywhere near as high a concentration of intelligent and interesting people outside the university as in the one I attended.

Hope something in there helps!