@JayHawkFanToo
Part of that is due to the shifting dynamic of collegiate ball.
For example, let’s take the 2010-2011 KU basketball team. This was the team with Selby as an OAD that eventually fell to VCU in the E8.
In college basketball, you are assembling a group of players that, up to that point in their basketball lives, have been stars and are relearning or remaking themselves as role players.
Selby was an on ball scorer in HS. Markieff and Marcus were the two main scoring options in high school. Conner Teahan was a star at Rockhurst in KC. Mario Little was a star in high school in Chicago, and was one of the top juco players in the country after that. Royce Woolridge once tossed up 40 in a high school game. So did Travis Releford. Brady Morningstar and Tyrel Reed were both big time scorers and stars in high school. Elijah Johnson was a ball dominant scorer in HS.
That’s almost the entire team! And that doesn’t include two of the better players on that team - Tyshawn Taylor, who was probably the 4th or 5th best player on his high school team, and Thomas Robinson, who was primarily a rebounder/ garbage basket guy in high school.
Brady and Travis both had to transform themselves from primary scorers (HS) to defense first players in college. EJ and Selby both had to move off the ball. Tyrel had to convert to a spot up shooter. Woolridge rarely played. Little had to convert to a garbage basket guy.
College teams are made up of high school stars (primarily) because the role players are not good enough to move to the next level. But only the very best high school stars can continue to be stars in college. The rest have to recreate themselves in different roles.
We saw it this year with Conner Frankamp transferring. Kid can play. He averaged 37 points a game in high school. But at KU, they aren’t running plays for Conner Frankamp every time down. They probably hardly ever would have run a play for him. So he has to find a new role that puts his best skill (shooting) on the back burner. That’s tough for a lot of guys.
It took Travis three full years to come into his new role. It took Brady two and a half. It took EJ two years to get off ball and he never got his on ball skills back in line.
@JayHawkFanToo is correct that poor coaching at the HS level also contributes to this. Most coaches are just happy to have a D1 level prospect on their roster, so they don’t spend time working with those guys to develop their skills in other areas to prepare them to not be a star at the next level.