I’m curious about kids who quit pitching but kept playing and how that transition went. You see the amount of kids pitching taper off and I’d love to hear about those kids in new positions.
It's only a problem if the kid hasn't ever practiced/played another position. Unless pitching is the only thing they do well, being a pitcher only is an incredible disservice to your kid's development. In DD's case, it was a major time expense for not much return. More effort now could be spent on fielding and hitting. Already a good IF, she learned to play OF, which paid off big time.
I think your better players can and will do this. “Being a pitcher” often gets ingrained into identity perception, and too many kids cannot let that go. Add into that our natural human fear of change …