Let me first say that this is not a moral exercise.
I'm not implying that these 10 college underclassmen should stay in school because it would benefit their development as human beings. Nor am I suggesting it will make them better basketball players in the long term.
Instead, I'm saying that these 10 would be drafted higher—and thus make more money—if they stayed in school another year or two. That's all.
Think of this as a cost-benefit analysis. The primary variable is NBA readiness, but it's far from the only one. Players also have to weigh the relative strength of their draft class, financial need, the possibility that they'll lose playing time to incoming freshmen and injury risk.
Those considerations made, the draft-eligible player then asks himself: "Am I worth more today to an NBA team than I will be next year?"
In the case of the following 10 college standouts, I'd answer very simply, "No."