This happens most places, even the blue bloods. KU has a player or two on their roster any given year who fails to ever come close to what was expected, same with Duke, etc. Look at our football team over the past few years -- guys who came in as highly rated recruits end up hardly seeing the field, transfer, and barely make an impact when they transfer. I agree with the general point, though, that the past couple years seem to have had more of these guys than usual. Lattin never made the strides he could/should have made, James has been up and down, and Kam obviously had a very disappointing season. Doo needs to have a good season to show that last year was a fluke.
I also think that Buddy and Isaiah spoiled us to a degree. Kruger has said numerous times they are the two hardest workers he has ever seen, and they obviously improved far more than what typical players do. They may not be stars, but I'd like to see Calixte and Reynolds set a great example for the younger players this season. Both those guys have all kinds of incentive to make it to the tourney for the first time, and hopefully they practice and play that way and it rubs off on everyone else.