A lot of it is mental toughness and personalities. A few years ago, while coaching JV teams i always tried to develop 2 pitchers each year. I would try to go 4/3 innings between the 2. I’d start one for one game and the other for the next. In a game where one was really on, i would let them continue as long as they were effective. By the end of the season the innings usually evened out. This goes well if you have players & parents that are team players. Out of the 10 years I did this, only one year was a problem. Parents of one player thought I was costing her a “scholarship” by not letting her pitch full games every game. AD, principal, and actual school board backed me. That’s how far the parents pushed it. Girl transferred after freshman year to private school for more exposure. Ironic part is she didn’t even play as a senior. Parents, be careful of what you wish for. Let your kids enjoy the game and they will be successful. Maybe not the star, but they will have lasting memories of playing for a team.