10 years from now college football is going to effectively be 2 conferences with like 20-24 teams each. A soccer type of structure might actually make sense, purely logistically speaking, although it'll never happen in our lifetimes because of all the regional pride bullshit.
You could have Group A and Group B, each with 10 teams, and then the rest of the conferences remain as they are without those 20 teams. Each season Group A only plays Group A (and as such crowns a national champion, likely with a top-4 team playoff), same with Group B who are playing to move up to Group A/not get relegated back to the "conferences".
Bottom 2 from A get relegated to B, top 2 from B go up to A (potentially as a result of a 4-team playoff at the B level), bottom 2 from B play a 4-team playoff with the top two "conference" teams, which is the result of like a 16-team playoff at the conference level.
I'd find it amusing.