Travel softball is a competitive and cutthroat business but a player should not be compelled to stay on any team just because the head coaches dad is friends with the players dad. I have seen too many teams that keep the same core players for years and the players and coaches get too comfortable with the team dynamics and the softball skills never fully develop. There is something unique about earning the right to play on a team that holds tryout and the possibility you may be cut every year. In addition, every player on a team should have to earn playing time. These daddy ball teams, by definition, can never cut a coaches kid or a kid who is friends of the family. This is why I am a huge advocate of playing on teams that have paid coaches that don't have family members as players. It's a totally different dynamic that is great for most players on these teams.
To OP, he stayed with this team for 4 years and his DD and he decided that they needed to move on. His "loyalty" to the team probably cost his DD a few years of developing other skills. I can't blame them for wanting to leave if they feel this is in the best interest of their child.
Everything is what you make it. Travel ball is definitely cut throat for most, but not all. I am not a daddy ball fan either but the non organization ball has a lot to offer in different aspects. There are good and bad examples of both, with paid coaches they usually stack rosters too deep and feel some obligation to play kids because they pay the same amount as everyone else. They are not gonna mess with their money so they will play kids to satisfy playing time requirements. So it just this weekend.
True she may have missed on some other skills but sounds like she got really good at the position she wants to play. At this point she probably would have been really good at OF but terrible at catching. Few would have given her a shot at catcher being a left and being so small