Shooting coaches aren't there just to show in live action the shooting style of JJ Red to a developing player.
They are there to observe in person through hours of practice the shooting form of a player.To try and correct said shooting form from the ground up through trial and error,fixing every aspect from feet positioning,release,shooting motion etc.
They are there to mold a players shooting form to what best helps that specific player,and not how to shoot in general.
Then they report said players progress to the head coach.Then the Head coach draws more plays for said player to check his progress in game.If something still doesn't work it's back to the drawing board.
Yes,the player's motivation and dedication is one of the most important aspect in the whole process.
But if your team does not help with putting you in the right position to succeed while offering you all the needed tools to do so,most of the time,you will fail.