do not grow with a team winning a couple of years. It takes a whole generation to increase a fan base by any significant size. Generally from alumni and their children of a certain demographic or ethnic/religious group. A couple of examples the B10 has seen a slide in their fan bases because of the Southern flight and the tendency of the children of those alumni to become fans of the local schools or schools where they go to school vs the traditional "family" school. BYU is different because of Religion. Notre Dame was because of religion in the early and mid part of the 20th century, but now finds itself losing fan base because the children of those fans again are rooting for the local teams.

There might be some bandwagon fans that jump on board a winning team over a couple of season or a dozen...but that isn't the core fan base and something that media executives would care about.