Jerykk - your name needs a k switched around. There was a lot of godfather stuff in the game. Sonny's death, all kinds of (cutscene) discussions about family business that were lifted straight from the movie. The 'mission' where you cut the head off of the directors' horse and put it in his bed. The mission where you go kill the heads of the other families as your son is getting baptised.. lots of stuff from the flicks.
And regardless if the game made $.02 or $2,000,000,000.00 - they made a deal for the license they have to pay for what they licensed.
And yes, Mario Puzo's estate is entitled to those profits, even though they didn't do anything directly to earn them. Guess what, in america you benefit from your previous family's success (or screw ups).