college presidents are not that bright and make stupid decisions. It doesn't help that Disney/ESPN is heavily involved, as there might be no institution so destructive to what it touches than the current Disney.
The 70 team model plus the G4 leagues makes sense, at least more than the current CFP, which is 90% beauty contest. Sure, this is the first year of the 12-team model, and 4-team model was equally bad to start (putting TCU and BU out at the last standings), so things can get better, but it is a bad start.
There is no objective basis for at-large teams. It is all about the "eye test", which is really just ESPN telling the committee what it needs to do.