The success of the Genesis especially in the United States, at least according to this movie, came from a “dream team” when it came to marketing and promotion. This team included Tom Kalinske, former CEO of Mattel.
For a time, this team at Sega of America held the parent company’s ear, and it led to the Genesis breaking Nintendo’s monopolistic stranglehold on the game industry. The Genesis succeeded because of some pretty amazing marketing and the success of Sonic the Hedgehog.
By the time the Sega Saturn came along, this team was gone, and I think it shows.