If you allow all conference champions access to the playoff, over time, those other conferences will raise their talent profile and produce higher quality teams that are capable to compete at a higher level than they are today.
This is partially how little Gonzaga became a power. Access to the tournament, win little by little over time and now they pull 5 star players in a 3-star league.
in football, the best players in HS know that they best path to the playoff is through a handful of SEC and blue blood teams. If access is less subjective, that talent can flow into other teams. After a view years of being coached up, and winning, Cincy then begins to pull 4-5 star talent and really competes
The schedule comparison and brand and fan travelling non-sense to arbitrarily determine who gets access is garbage. It serves to allow them to get richer and bigger to further build a wall to close out access to 110 other teams.
In today's structure there is a no-win situation for 110 teams. Even is you make a bowl game against a "superior" opponent to prove yourself and win, if its not a playoff game, the big school says that they didn't care/weren't motivated/blah blah blah. This would happen if Pitt beat Alabama in the Peach bowl.