I certainly understand the importance of making a boy complete his commitments. I guess it really depends on the situation. My experience was that most teams had 6 to 8 core players and the balance of the roster fluctuated for various reasons - playing time, overload at a positions, coaching issues, competitiveness (too much - too little) family moving, and PARENTS. This happens from elite teams on down.
I ran a team for two years and had a "free market" approach to it, as I was only out to try to get a group of kids to learn how to play good baseball. So if for whatever reason they thought it would be better for them to be on another team then I would help them get on one. In the end I think it was healthy for kids to experience other teams, coaches and team dynamics, particularly at young ages. Looking back on it now, my personal opinion is that this whole elite team thing at young ages is way overblown. (for another thread)
Frankly, in most cases I think it was the parents who created "commitment" problems not the kids. On the elite teams this tends to be more prevalent since parents are paying more and expect more. They also tend to have more unrealistic expectations for “Johnny” From what I have seen it has always been this way and will always be so, just the nature of people.