I'd have to agree with you here. For me, gaming is all about the story and I have yet to find a story that I loved SO much that I didn't want it to end at some point. Harry should finally face off with Voldemort, Luke should finally face his father and save the galaxy, and Mario should finally find the princess. Preferrably, all this should happen before I turn it off because I feel it's wasting my life.
It seems so many games nowadays will carrot you as long as they can until you leave the franchise in disgust or boredom rather than satisfaction. Kill it till it's dead then reboot or revive it till it's dead again. Wash, rinse, repeat. This zombie-like creativity in our producers AND consumers is unfortunate. There is nothing wrong with ending a good thing while it's still a good thing and then moving on to something better. Sadly, it is, of course, all about the amount of money that can be sucked out of our emotional attachment to a character or a world or a cause. Hence, teenagers and college kids are revolutionizing our industries because they haven't figured that out that it's all about the money yet. As they see it (and we should as well), there are still great undiscovered stories, worlds, and characters out there. We're just too scared or too lazy to explore them.