To a P5 team, the season becomes meaningless and the teams responds with losses to directional Illinois , crappy Florida teams, poor Ohio teams, directional Carolina teams.
Fans and media lose interest because the players lose interest.
With a league, you always have a division and the league championship to play for. One out of conference loss doesn’t mean the end of the season. Win the league and you go to a NY 6 bowl game.
There will be more interest in players, fans, media