the problem is that sometimes, their is nothing left to teach the player. Maybe tactics wise and what he should do on the park, but i wouldnt be surprised if many times the player goes for glory instead of the safe route
Like when Henry went to Barcelona, what could Frank Rijkaard(not sure on spelling) teach him? He was one of the best players in the world At the time and he wasnt going to become any wiser or more knowledgeable of the game
All im saying is that its not always the managers fault, if he has bad players, what do u expect of him. Its like expecting a hairdresser to give a bald man a mullet, sometimes, you just cant.