Sure, Gates/Jobs/Zuckerberg/etc didn't graduate college. However, you have to remember three important facts: they all at least started college, they all stayed until they had an insane success on their hands and they all met (or at least worked with) their cofounders in college.
College isn't for everyone, and it's definitely a broken system. However, it's about more than just about the classes -- spending 4 years on a campus with thousands of other young people who are all there to learn and explore is transformative. You don't get that once you hit the real world.