What I meant was guys staying, redshirting their freshman year, coming off of the bench for a couple of years, and becoming something their 3rd/4th year in the program. A la Frank Kaminsky, Jordan Taylor, Ben Brust, Tyler Wahl, Bronson Koenig, Jared Berggren, to a lesser extent Nate Reuvers, D'Mitrik Trice, Johnny Davis didn't redshirt, but he didn't start any games as a freshman and was a high 3-star recruit. Happ was good as a freshman, but he redshited and learned under Kaminsky for a year while never playing.
If they go to a different school, they don't get the same development. Different coaches, different system. How many of those guys would have stayed had the portal existed? We'll never know.