Do IU fans realize those banners came with a price tag? They created an egomaniac that was not an IU guy, but a Bob Knight guy. He began to destroy their culture 5 years before he was shown the door. You could see it in the way his teams played, the lack of respect shown to his fellow coaches, how he interacted with the administration, treated those around him in the athletic department and patronized his fan base. His kids had no confidence and probably weren't entirely sure which bipolar maniac was going to show up day to day. He gave a middle finger to not only the university, but the fan base on his way out. They've been wandering in exile for 20 years as a result and are possibly just now finding a culture. Knight built IU and destroyed it on his way out. If Keady did that to Purdue I wouldn't want anything to do with him.
Btw, what has Knight given back to the game? Does he have a coaching tree? Nope it was all about himself and a few inner circle guys from the 70s and 80s. He kept a couple of gray haired guys sitting next to him that would put up with him (and I think he even trashed them on his way out). A travesty and embarrassment how he treated Alford. His biggest disciple was Dan Dakich. (Both X and O geniuses by the way - there is nobody that I enjoyed listening to broadcasts more than Knight and Dakich when they were coherent and serious about the game.)
Conversely, Purdue has known its identity and culture for over 4 decades. Keady has quietly supported the program without fanfare. The Keady/Painter coaching tree is substantial - giving back to the game, building a culture, a program and caring about the university.
The banners are impressive. Success is hard. Sustained success is even harder and I'm not sure Knight and IU had the character to make that happen.