Everything has a price, we are talking of a big amount of money here and I don't think Manny's camp would not think twice before making a decision.
Regarding your statement, do you have an article you can share that Manny's camp won't allow this to happen?
Everyone has their opinion regarding this match up but if both the promoters of these respective fighters want to earn the money then this fight will happen. It is true that Bob Arum the promoter of Manny Pacquiao wants another fighter Terence Crawford to face Conor McGregor and we all know that Arum will not make fights what the fans wanted and he is not a good promoter in my opinion even though he is a boxing promoter for decades.