If you could buy stock in one of these fighters and the deal is you receive a percentage of their earnings from now until 09-16-2025. So this is not about necessarily who you think is the best fighter but who will have the most success at the box office and receive the highest purses.
My pick is Anthony Joshua.
The lower weight guys typically don't draw that much money. The heavies are good options, Wlad will probably retire in the near future and Joshua and Wilder have good a chance at being the guy.
I went with Canelo. He is already a big draw and carries the Latino juice. I expect his stock to go up big time after the Cotto fight. He is also only 25, so he is further along as a draw for his age than anyone else.
I would take GGG over Alvarez as I think after they fight, Canelo will not be worth very much. I think Golovkin will last for another 6 or 7 years and will make more money than Canelo in the next 10. I would consider Joshua but that division really has little competition and the heavyweight division has not exactly been a PPV cash cow for a very long time.
I don't really see anyone with a bigger up side, PPV and profit wise, than Golovkin. Even if he has a shorter career than a number of the fighters on your list. A fighter can only be profitable if he has the competition to make fights that people will pay to see. I think people will pay to see GGG more than anyone on the list, regardless of who he fights.
Now if Canelo learns to speak English and becomes more fan friendly than he is now, he should have a great career after GGG leaves MW or retires. But until then, GGG will be the man attracting the fans to the sport for the next 5 or 6 years.