From a customer retention standpoint, Nebraska is almost impossible to predict, mainly because we aren't a normal supply/demand situation nor is there another "market" that can take Nebraska fans. The trope of bored Nebraska people is real, people just don't have that much to do, and a husker game weekend is still pretty cheap and awesome compared to going to some dry reservoir, or the loup river for the weekend.
I do not think the AD worries about losing fans in a massive migration, I think he worried about becoming ISU. You can't forget that. at the point of the extension, we were looking at a possibility of a 7-3 start, with 9 wins certainly possible with wins over UCLA and Iowa or Penn state. Dylan was still healthy. Lets say we beat USC, then UCLA, then Penn State...we are 9-3...no extension even when Rhule requested, Rhule would have to feel targeted and not likely to be retained by Dannon in the future. Dannon certainly should have waited until after Penn State to make the decision but he was afraid of losing Rhule to one of the 20+ jobs that might open. He loses his roster and has to find a coach in a terrible market.