What were the rounds for the two that didn't? Surprised there were any, really. Seems weird that a team would spend a pick on a guy without a verbal agreement. I suppose maybe teams sometimes take guys they really like, guys who say they want more, in the expectation that they'll settle for what you can give?
You seem to be looking only at the teams as the source of lack of agreement. We are talking about young men here. I am honestly surprised there were so few instances out of 300 young men where there was no agreement. I would have expected at more than that many young men who simply changed their minds and adopted absolutely unrealistic estimations of their own worth.