One other thing with pitchers specifically is many coaches at the younger ages want to win, so they'll pitch their #1 most of the time. That means #2 and #3 are fighting for scraps -- maybe a pool game or friendly here and there. After a while they figure why bother putting in all the time, and their parents figure why bother paying for lessons, if they're hardly ever going to pitch anyway.
In some cases that's probably a good decision. In others, though, perhaps not. Kids mature and grow at different rates, and that girl who can't break a pane of glass as a 12U might turn out to be a pretty good darned good 16U or 18U pitcher. I've seen it happen. But if she's been discouraged by a lack of opportunity we'll never know what she could've done.
In some cases that's probably a good decision. In others, though, perhaps not. Kids mature and grow at different rates, and that girl who can't break a pane of glass as a 12U might turn out to be a pretty good darned good 16U or 18U pitcher. I've seen it happen. But if she's been discouraged by a lack of opportunity we'll never know what she could've done.