A number of the school playing P-5 football have severe problems with female demographics among the students. Women just don't support football like men. I could see a shrinkage to about 36 schools willing to play at the highest level and having the support geographic situation to continue. Then a division below them that still play football, but not every week with the biggest boys.

Looking 30 year out I came to something like:

Big 9 - NC State, VT, PSU, OSU, Michigan, MSU, Notre Dame, Wisky, and Iowa
SEC - Miami, Florida, FSU, GT, UGa, Clemson, SC, TN, and Auburn
SWC - Bama, Ole Miss, MSU, LSU, Arkansas, OU, OSU, Texas, and TAMU
Pacific 9 - Washington, Oregon, Cal, USC, Arizona State, Utah, TT, Nebraska, Mizzou

Each school has 8 conference games, and 4 games to spread over each other or the lower tier:

ACC - UK, Vandy, WVa, MD, Va, UNC, Duke and WF
Great Lakes - BC, Syracuse, Pitt, Indiana, Purdue, NW, Ill, Minnesota
Mountain 9 - WSU, OSU, Stanford, UCLA, Arizona, Colorado, Kansas, and ISU

The smaller tier can be basketball oriented and focus spending on athletes in that direction. They can still field a football team but not have conference competition on a scale that their academics, geogrpahy, or alumni profile doesn't support. This tier could interact more with the Ivy League and Big East.

I may be wrong, but I can't see the current type of football surviving at some of the institutions. I'm sure I will be dead by then.