Trust In Him, I guess the question is “would he have been the same hitter without the constant coaching?” If nobody changed his swing, was there a need to pay for those lessons or were you simply paying for BP? I guess it depends on perspective. I suspect the repetition was the valuable aspect of those “lessons” and not any technical instruction - because your son apparently has an innate ability to hit the baseball.
Like Cabbage said, and Trust In Him has illustrated, everything is different for every player.