If the conferences are concerned about losing revenue from championship games, they have to factor in the loss of revenue if the conference game loser gets bumped out of the playoff.
That, and the expanded playoff means even more games. So it’s possibly 12 regular season + a conference championship + playoff first round (if no bye) + up to 3 more games if you get to the championship. 17 games? That’s a lot of time, travel and wear and tear. In addition to you know, actually doing school which NFL players don’t have to do.