In terms of actual narrative a third one would be pretty redundant.
For us fans here maybe but for those promoters who like to make money, they can easily hype the rematch again so they can sell this fight.
As a boxing fan, I can compare this with a Mayweather vs Pacman possible rematch and fans like to see it although it's obvious that it was Mayweather who easily win against Pacman in the first fight, this is no different, big names fight big names will hype the fans.