Michigan is a huge brand in college football and fans will watch to support the team and its rivals fans will watch hoping Michigan loses. I believe Howard Stern was quoted about his audience (paraphrasing) "The listeners that love me will listen for an hour, the ones that hate me listen for 3 hours". Ask an Ohio State fan, they much rather enjoy watching a Michigan loss then a Ohio State win any Saturday.
With Fox, ESPN, ABC, and the Big Ten Network trying to fill a primetime game every weekend, Michigan becomes a big candidate for a night game.