Who said anything about something being free?
The objective of adjusting or changing technique is to correct deficiencies. I offer opportunities and methods to correct deficiencies which the player can use if he wishes. If he does not wish and if the deficiencies are not corrected, he is at risk for reduced playing time.
Example: A player has a problem with anger control. I offer him ways to identify and manage it and he rejects or, more politiely, refuses to take the steps necessary. His temper tantrums continue with throwing his helmet after a strike out.
The behavior is not acceptable and the player is benched. Consequences. Cause and effect.
Same goes for flaws in fielding, pitching, or batting. Correct the flaws as I suggest or by some other method but get them corrected or suffer the consequences.
Have you ever seen coaches arguing with players who do not want to change? Why? Offer opportunites to correct deficiencies and let it go. Move on with those capable and willing to learn.