I saw online this morning that my beloved NY Mets are changing hitting coaches once again. They
fired the first coach about halfway through this season and promoted the guy they let go yesterday. When you compare the team's batting results under both coaches they are very similar.
These parallel statistics could point to the ineffectiveness of both men to identify problems and communicate solutions. It could also be very revealing about the players they are attempting to improve. Perhaps the issue isn't with the coaching philosophy, but the talent and focus of the players they are working to help. If they continue to bring in hitting coaches and see the same results it might hint of a problem that isn't related to leadership or instruction.
At some point, a leader is doing the best they can with what they have. The results may not be at the level that is hoped for, but changing the leader may not elevate the level of performance either.