The kids who become the top high school players came from the pool of 12U studs. However, many 12U studs fail when they get on the big field.
Only four from my LL all-star team (only game in town then) played high school ball. Two played college ball and were drafted. The biggest, baddest flame throwing, hit the ball out of sight player was 5'9" in LL and 5'10" in high school. It wasn't that the other ten all-stars weren't good athletes. Nine played a high school sport. They just weren't good enough to be high school baseball players. One discovered chicks dig guitar playing lead singers and stopped playing sports.
A chubby, klutzy kid who didn't make all-stars became a 6'4", 245 pound flame throwing MLB pitcher for six years. He didn't pitch until his senior year of high school when the coach needed arms. He had been catching. The next year he was pitching in the SEC.
A kid from a rival LL ultimately became a Legion teammate and college summer ball teammate. He was hitting twenty homers a year in LL. He didn't bother with Babe Ruth level ball. He was too busy developing his golf game. I saw him hit some balls out of sight in Legion and summer ball. He was a first round pick out of college. He was doing great in the minors when he got injured a couple of times. Here's fate: Had he been one of the prospects packaged in a trade offer he would have been starting in the majors before the injuries occured in the minors. The MLB front office refused to include him in the trade. The deal fell apart.
There are four high school prospects from my son's '05 LL all-star team. Seven of the other eight are high school prospects in other sports. The eighth is too small and weak (5' with 5'6" dad and 5'1" mom). He peaked at 10U when he wasn't drastically smaller than everyone else.
The stud pitcher a year ahead of my son in LL, has already blown his arm out from playing LL and travel at the same time. Muscle distress has snapped his arm twice in the last three years. He's not expected to pitch again after breaking his arm in three places (one place twice) in three years.