If there's one thing about Hollywood you can always count on, it's that a movie that racks in $100 million dollars that's not based on a historical event or a novel, will always spawn a sequel. In the world of gaming, it works pretty much the same way. The only difference is that $100 million dollar movies are often original and push for something exciting in a genre that has yet to be done, or is highly anticipated (i.e., superhero films, remakes or graphic novels.)
$100 million dollar games happen to inflect a specific trend for a very specific demography, sometimes bypassing some things such as storylines or character depth. So why is it that games can be more successful when it comes to a sequel, than a movie?