I seem to recall a time when if team A was 6-3 and team B was 6-3, but team A beat team B team A was the champ
There was nothing "co" about it. Team A holds the tiebreaker, thus team A is the champ. For some reason that seems to have been lost in the last few years. The most egregious case was the Baylor-TCU "co-championship" a few years ago.