Well the reason why Mario sustains itself and Assassin's Creed clearly isn't, is because Mario relies on actual fun mechanics for entertainment rather then the delivery of a narrative. You can make games on their 'gameing' merits until the end of time. However, if all your game has going for it is it's cinematic merit, then your gravy train has a final stop, and it's sooner then you think. You can't tell a single story forever, people will just get bored. You know what isn't boring? A trampoline, and when it does get tiresome a quick break often fixes that. This is why I prefer the games that are more like a trampoline then a movie. If I wanted to watch a movie I would go watch a movie, I play games to play games and have fun. The fact that you even think japanese stories are important just shows you have no idea why people choose to sit down in front of their TV with a controller instead of going to a theater.