Instead of doing one and done.

IMO, there is little incentive for a player to do this, except avoid schoolwork.

Coaching is better in the Power 5 conferences, especially at the top end.
Accommodations are better, with luxury dorms at Power schools.
Players become better know as college star than toiling in the G League.

G league pays really poorly - Andre Ingram made almost as much in his one game with the Lakers as he did all year in the G- League.

Make G-League salaries at least $75K, more like $100K, and get better coaching, and then it may be a reasonable landing spot for a 5star recruit. Unitl then, it's for guys hanging on who don't want to go to Europe to play ball.