The creators didn't get shafted or fleeced or anything. They sold away media, merchandising, etc rights an intellectual property (i.e. Superman) and then after seeing the massive amount of revenue that is generated they feel entitled to a share as creators, but they sold that away. Doesn't matter who created what. If you still away the rights or use of the IP then that's just that.

That's like selling some old beanie babies then after finding out they were sold for millions wanting a cut of the... That's not how business works. The creators of Superman sold away the rights. Rather they knew the long term value or not is irrelevant. They even were gifted an agreement that let them collect something when they should actually collect nothing that states specifically THEY MUST NO LONGER BRING THESE FRIVOLOUS LAWSUITS EVER AGAIN.

This is no different from Marvel and Sony. Sony owns rights to media productions of Spider-Man and Marvel realize their mistake and wanted the rights back, but at least they were able to come to some sort of concession for the betterment of business and the fans.

DC creators however are just a being petty and childish about something they chose to sell away for so cheap so only now complain about their own poor business decisions. It's ridiculous...