...then why do only about 10%-15% of the 18U pitchers we face "have" a ChangeUp?
When I say they can't throw it well I mean they can't throw it for a strike on command.
Not necessary to be able to throw a change up for a strike for it to be a fantastic pitch to use.
That doesn't even make sense. If you can't throw your change-up for a strike we tell our batters not to swing at it. End of story.