Using the phrase "instead of" is based on your completely uninformed speculation. You have no idea why O'Leary is in the job and Cooks is not.
You have no information if others were considered. You don't know if it was a choice of either Cooks or O'Leary. You don't know if Cooks decided for any number of reasons that he didn't want the job. You also assume, based on stories like you cited that Cooks was the "most likely internal hire." Fact is those stories are idle media speculation based on the fact that Cooks is certainly a qualified experienced coach who is already on ND's staff as opposed to any specific knowledge of what the process and ultimate decision was.
Speculation is fun and fine but you display your agenda when you post things as you did in this case
By the way, I was aware that Cooks was on ND's staff and would be a logical possibility for a regular coaching position at ND. Heck he was mentioned as a possible DC. So again, your speculation displays more of your overt ignorance than anything else. You missed again!