If you're an incredibly self-motivated and intelligent person when your 17 or 18 and you are passionate about learning and excelling, then sure, skip university if that's what you want.

I'd venture to say it's more rare than not to find someone who could successfully utilize 4 years and $150,000 in an unstructured environment. It's unfortunate that this is the case, but I just don't think it happens very often given the emotional maturity of many high school students.

I "did well" in high school because it wasn't difficult to do well by grading standards. College was when it all clicked and I developed a passion for learning. Obviously this is my experience, but I see this sort of thing in those around me (and many that still, even after college, wouldn't know how to use that money in a truly beneficial manner). University often puts you in the company of some intelligent individuals in a learning environment, as well as the opportunity to meet some great mentors that help mature.