Unfortunately, when integration occurred Black Players fled from the Negro League to the Major Leagues causing this Black Owned economic industry to collapse. Once they got to the Major Leagues, many of them became MVP's season after season.
MLB to this day refuses to acknowledge them as professional even though they've acknowledged other professionally organized leagues of the time.
The priority of owning your own and not caring about another groups acceptance has never been more vivid than the rise of the Negro Leagues and it's demise due to Black's seeking approval and acceptance from those that don't care about them.
If our modern day athletes came to this conclusion we could have our own industry and financial engine nearly overnight in same fashion as how the Jews did with Hollywood.