As long as there are fans that are willing to pay this exhibition match, it will continue. The Paul Brothers and Floyd Mayweather are making huge money. Even those former boxers and MMA fighters as well.
That's true, only the fans can stop this madness because without the fans they will not make money. It's robbing the real boxing fight because the revenue might be split or it won't be able to maximize the profit of the professional fights, but it's not the fault of the promoters of exhibition fights because boxing whether it's professional or exhibition still belongs to entertainment.
The success of this kind of events always rely with how the fans support the fight, though most of the time promoters knowledge in attracting the social media fans makes it more successful, the noise around the public setup and the fighters that they will introduce always reflects to how the fans will engaged and buy the tickets,
I'm sure that the logic behind is to keep making money and both the fighters and promoters will keep finding ways to make sure that in every event that they will introduce, the fans' interactions will be there to sell the tickets and views.
Promoters are really smart, they rarely made mistakes because this is their expertise and they have people to sell the fight. This particular fight is not hard to sell, we have Manny Pacquiao, a legend, so whoever his opponent is, it doesn't matter because people will only come to watch Manny win by punishing his opponent.