Just like what you mentioned about Pacquiao and how things went between him and Arum.
Money talks, as always, with sports that have a huge amount of money that flows each time well-known fighters are at stake.
Not siding with Arum but somehow, we can't hide the fact that his big influence also plays a role in why most of his top fighters are able to earn big money throughout their career. What if Pacquiao didn't land on a big promoter, I doubt he will have some big fights while at the peak of his career. Bob Arum, being a professional businessman in this industry knows how to make big revenue in a certain match. Of course, without a big money flowing on a certain match, how can they even pay their boxers with that guaranteed money (that was different from purse split)?
Boxing is really business at some point, but somehow a boxer can build a legacy while also doing business at the same time.
I fully understand both your side and it's true that nothing can be done with any fighters career if there' no big promoters that will handle the job, and what we witness with Pacquiao's career and those many other fighters who changes their lives after being promoted by Arum, nothing but they all gain huge compensation with how Arum manage their finances and the negotiations with the fights that they take.
It's all business and whoever has that big influence always has the advantages of earning more.
He just use that connection and established a fighter's career to make sure that he will suck lots of money out from the fighter's legacies.