"You can have all the movement in the world but the magic equation that is most effective at keeping hitters off balance is the combination of velo that is hard to catch up to along with secondary stuff that is considerably lower velo than the FB."
Cabbagedad,
As usual, very thoughtful and accurate reflection on how things can be so much different at the next level. If I could add to your thought, it would be that, at the next level, those pitchers who succeed will command each of those pitches in most counts and then be able to adjust for the 2nd and 3rd time through the batting order. Without knowing more, I would have a suspicion that some of those JCG sees struggling may not have command of their pitches, especially when college hitters make their adjustments.