Both groups you mention are separated by two years... Laettner/Davis were two years ahead of Grant Hill. Battier was two years ahead of Williams/Dunleavy/Boozer. James was a redshirt senior, so he was initially three classes ahead of that group. And Duhon was a freshman on that team and started throughout their run through the tournament, so 2001 really had contributions spanning 4 classes.
Your point is basically that on good teams you tend to have a cluster of good players within three classes of each other. I don't think many people would disagree with you on that. And I get that we potentially have such a cluster in our future with the incoming freshman class and returning sophomores.