Painter is doing what a lot of coaches are not willing to do (like Indiana).....they do not and will not take a kid who is not part of their system, they will not take a kid if he isn't willing to redshirt and they won't take a kid who is unwilling to try and be a good defender.
It took awhile to flush out some kids, but around 2014 or 2015, they lost two kids to transfer that were starters and double figure scorers and the Purdue fanbase went ballistic (except for a lot of fans who didn't like the selfish me-first kids who were transferring out).....instead they went strictly unto this mode of team first.....and while Indiana continues to pile up 4* and 4*, Painter (like Jay Wright) recruit kids that fit their model.
Indiana is now on their 3rd coach Tom Crean, Archie Miller and Mike Woodson and Purdue has beaten Indiana (I think) 10 straight times.....
I am not sure Purdue has enough talent to make the Final Four (they're still limited in some spots on the floor and inconsistent at the point guard position).....
When you also are willing to pick certain kids and they're willing to redshirt, you avoid having to go into the transfer portal......Purdue and North Carolina are the only 2 Power 5 programs, who did not take on a transfer in......they're connected and team chemistry is much better.
When you have kids in your system and stop mixing in new kids each and every season, you can add layers and layers to your offensive arsenal, because the kids understand the system better and you don't have to start over each spring/summer......