Once we get relegated we can get some fun games against our new regional rivals Northern Illinois and Western Michigan in front of 20,000 people
That won't happen. If ISU is "relegated" we will be among a number of current P5 teams in the same situation. Based on a 30ish team Super League.
I would think Iowa State, KU, K-State, Okie State, Cincinnati, Louisville, Pittsburgh, Iowa, Northwestern, Purdue, Nebraska, etc. would not be invited to the Super League. Conference affiliation would not give teams an advantage. It's going to come down to football tradition and TV eyeballs. ESPN, FoxSports, etc. will have a voice in who makes the cut.
Schools like Minnesota and Illinois might not have strong recent football traditions, but could be invited to make sure the Chicago & Minneapolis markets have a team. Whereas schools like Nebraska and Iowa might better recent traditions, but don't bring a lot of eyeballs.
I am not convinced a Super League is a done deal. The key are recent/near future legal decisions. What the tiers look like will determine where schools fall. When the Notre Dame AD mentioned schools possibly licensing their names to outside sport organizations, he insinuated Notre Dame would not be part of such a structure. If that is the structure, there is the thought that other strong academic schools might not join such a structure. Private colleges with large endowments like Stanford, Duke, USC might be hesitant as well.