I'm kind of torn on this topic. I personally hated high school. I was one of those kids that only took AP and honors classes but my good friends were the ones that the school system saw as "throw aways." This essentially allowed me to see both sides of the school system. I hated it. The "gifted" students got all the praise, recognition, and support while the "throw away" students got the worst teachers and were given the cold shoulder when they asked for help. The whole system, in my opinion. is rigged to create scholastic machines. I'm glad I broke out of it.
On the other hand, I really do believe that the only way anyone will excel in life is if they really want to. If someone doesn't go to high school and they don't find a passion for a specific field or subject, they won't make the attempt to find more information. In this case, some people do need the guidance of a curriculum. So it can really go both ways.
Ultimately, school in general doesn't guarantee success or improved knowledge in any field, subject, topic, etc. It all comes down to the student and their willingness to discover new things.