They're really talented, but they're really young. This is the challenge with recruiting one-and-done players. They don't have any time to REALLY learn to function to the best of their abilities as a team.

If Coach K was able to coach that group of players for four years, and if that group of players was committed to being college basketball players for four years, and winning for their school (as opposed to just putting in the NBA-mandated year before going pro), they'd probably wind up being really good.

But they're just too young. They might still win championships here and there, but in general, they're not going to perform to their talent level year-in, year-out, due to youth.

Having said all that, Coach K is getting older. He's probably not as good as he used to be (as a defensive coach in particular, but that gets back to the youth of his players again).