I don't think sale speed itself dooms a franchise. But blind loyalty will eventually. I think it's pretty proven in todays corporate environment if a company can produce trash and make more money off it then they certainly will do that. Of course this only happens with major successes and with that major success legions of both fanboys and haters will arise. At first the haters will be to critical and lose creditability and the fanboys will be justified. Then the corporate eye sees a determined fanboy crowd that will throw money at anything to show the haters who is boss and milk it. Slowly, and often silently, as this goes on fanboys start to diminish. They start to figure out they were dying on a hill that will never be the hill it once was. Then the hater crowd starts to get stronger and more numorous until you are left with only fanatical fanboys that will buy dozens of copies just because and an insane echo chamber of hate cult. The ratios usually always slide in the haters direction, and its usually justifiable, until the franchise realizes it needs a winner again and actually puts out a winner again. Then the ratio shifts hard and fast again to fanboys. You know, the we are back type of fanboys. If its enough the company knows it can drop a few more trashers because sales will be good enough. If its not the franchise will dip out for a while and have a reunion tour release in a few years once memories on the subject fog up a bit. Things just cycle again. Just another day in trying to get people to pay more or less weather your product is good or bad.