Northwestern is in Evanston playing in a minuscule stadium (that they are going to replace). There is very little fan support outside of current students. It's hard to get there, parking sucks, and you're competing with the Chicago activity scene.
There are vastly more Notre Dame fans in Chicago than Northwestern. BYU will probably fall out with a little flavor of both of those institutions. Recruiting will be hurt by good academic standards and a more limited recruiting base, but there will probably be a higher recruiting success rate closer to a ND than a NW.