Most are in the last week of the season (with a few exceptions like Iowa vs ISU). Early season games get tons of attendance and viewership because the weather is nice and the fans are full of hope for the season and because everyone missed having football to watch. But the end of season doesn’t have that, so the rivalry games are a good excuse to bump up interest in the late season. Plus it takes advantage of people having time off for thanksgiving. So I don’t think they will mess with it at all. The only thing likely to change is that Army v Navy might have to share their weekend with more regular season games.