They are so good that they are used to freestyling and making the play. While that might have worked for them in HS... they are playing on a whole new level now, and going off script will leave them out of position and vulnerable. You see that play after play. It is not that the defensive call is wrong. It is that one player decides he is going to "make the play" or doesn't trust the player the play seems to be going at, and gets out of position. At this level, most other teams are able to take advantage of those types of weaknesses.