A pitcher prefers to throw only movement pitches. But, when a pitcher at any level needs to throw a strike, the pitcher is going to throw a fastball.
I've only been around the game for 25+ years now, so I've not seen everything...but I haven't seen a college pitcher get through a game without throwing a fastball. The idea that 14Us go out and throw entire games seems a little far fetched to me.
Not to Highjack this but where does this notion of never throwing a fastball come from? It's the easiest pitch to put where you want and as you said, thrown when you need a strike. I think it should be used to get ahead in the count then it makes it easier to get girls to chase movement pitches. Nothing wrong with a FB on the hands that only gets fouled off. The bigger point is not to miss with it.