It was to keep him. Not sure what you wanted him to do
Let him walk. A .500 conference record with one fun weekend followed by a no show in the dance wasn't that impressive.
Everyone saw the losing season coming two years ago. It was the gap in talent left by Fred quitting recruiting a year before he left. I fully supported Prohm through that and was optimistic about the future with the talent he had coming in.
Last year should have been better. We were wildly inconsistent and the wins in KC seem to have masked/made some forget those problems. Had he built on the conference tournament title with a good showing in the NCAA tournament I could see your point. He didn't. With that in mind, I think you're overselling how upset a lot of people would have been if Prohm left on his own. There were a LOT of pissed off Cyclone fans after that floater we left in the bowl against tOSU.
Prohm has been great at capitalizing on getting hot in early March and propping himself up on that success. His larger body of work isn't that awe inspiring. Good or at least above average? Most of the time. Irreplaceable? No, and I don't MOST Cyclone fans would have come after JP with pitchforks and torches if he somehow got away.