Imagine having twelve of the best programs:
Alabama
Clemson
Georgia
Ohio State
Michigan
Notre Dame
Oklahoma
Texas
LSU
Texas A&M
USC
Oregon
And they all play each other, with the bottom three teams falling out, and then the three teams from the lower division moving up the next season. You could have maybe 6 or 7 such divisions. Actually the most interesting games would involve the teams trying to avoid the drop.
Texas and Texas A&M are consistent underperformers. Not worthy of inclusion in your list.