At least this guy is totally honest about the reason he doesn't earn a percentage of sales of the extremely popular games. I'll let you guess which person in the photo below is the author:
"I was stupid enough to sell them rights to the whole bunch," he says. "They offered me a percentage of their profits. I said, 'No, there will be no profit at all - give me all my money right now! The whole amount.' It was stupid. I was stupid enough to leave everything in their hands because I didn't believe in their success. But who could foresee their success? I couldn't."