My sons AAA city team has only 2 guys that went on to college. His regional all star team had most of the players go on to college and the minors.
A great example of a guy who was not great until he reached 16-17 was Nick Weglarz (94th pick 05). He was cut from the Niagara Falls AAA team and that spurred him on. I personally feel that too much early success can be a bad thing.