players leaving to go to another team is entirely different issue than a player looking in the mirror and deciding "I'm done playing sport X." Whatever that sport is. and there are a bunch of life factors that can cause this being done. Parent death, injury, financial, love interest, academic or career plans, etc. None of these are really controlled or influenced by the coach and it's just part of any sport.
Now, players leaving to go to other teams, could be directly related to coach of current team or not. I've seen many players over the years commit to a team in August being sold a bill of goods as to schedule, play time promises, overrall skill of the team, etc, etc, etc.. And it could be deliberate deception from the coach, or not. Very hard to blame a player and expect them to stay when promises and expectations are clearly not being equal footing.
Example, Say player X commits to 16u Chico's bail bonds after being told that the team is solid and will be playing a high level schedule with chances to be seen by college coaches. First couple practices come and go with minimal turn out (9 players, 2 pitchers, 1 catcher), minimal coaching and just overrall bad vibes. And then comes the first tourney date in Sept, and Chico's gets destroyed in a little local, lower level 4 team event. Then they get smashed few weeks later in another smaller event. Big event comes in October and although all 9 available players give it their all, they are not competitive in this event. Now the parent's of Player X, haven't seen coach 1 watching Chico's getting their beatings enroute to the 0-13 fall season, are observing obvious lack of skill of players, and just overrall unhappiness. How is the world can anyone expect Player X to continue on with commitment to this team, when it is obvious to all that they will not being playing a higher level schedule the following summer, do not have the skills to compete and promises made in August, have no chance of being honored??? You don't, Player X, looks around sees other teams winning tourneys, trys out and move on.
Yes, this is a simple ficticious example, but one that happens very often. Or the promise of playing every inning at say SS or C. Sure, player X is playing every inning, but they are losing every game? Do you expect them to stay?
Have not even touched on the daddy / Mommy ball scenerios that seem to arise every year, every age, every org. The head coach that plays DD at SS and she bats 3rd regardless of skill, results, rule breaking or other talent on roster. Again, cannot blame people for seeing "writing on the wall" and making decisions.
The biggest problem that I see is teams that are truly clueless as to their true skill level and classification. They claim to be "Level J" and in reality, they are in no way, shape or form a Level J team. They are really Level J minus 2 steps and that's a stretch. May have never seen a true "Level J" team, have no clue as to what a "level J player or roster looks like, But they won the local "Hittin' Kitten Open tourney last year, so they have to move up to Level J now cause they are really that good. Reality checks really hurt when team rams that wall at full speed.