I don't know if the players stopped listening to him. That's a judgment call for Pohlad to make. If true, that's a reason for firing him. I assume Molitor is a professional and is providing feedback for his players. Are the fundamental errors more than the average team? How much responsibility falls on the manager vs. the player himself? MLB caliber players as you said know the fundamentals, and they should be able to do it day in, day out, regardless of the manager. As far as coaching, training, and fixing problems, that's also not just on the manager. Especially in this era of baseball. Wasn't it Falvine that drew up the plan to fix Sano earlier this season? They have an analytics team to dig up video and data to help coach, train, and fix problems.