Black Sail faced numerous challenges in its early days of entrepreneurship.
One should know that not everyone could enjoy the treatment of splitting their earnings sixty-forty. Others would want to kneel, but couldn't even do so.
In the East Sea Domain, one could only bring their goods to sell at Heavenly Port, nowhere else would work.
The three giants monopolized the area completely. If you bypassed them and directly delivered the goods to a Noble Master's white glove, the white glove would merely scoff.
A stable connection was already established, and white gloves were more than one. If you broke the rules, don't blame them for not giving you any goods later. If the Lord above you blamed it down, you were the one responsible.
Only somewhat capable Pirate Gangs could enjoy the split of sixty-forty.
Some ragtag groups looted some junk back, and if the giants didn't want it, they'd simply get rid of it—sell it if you want, or leave it if you don't.