The search for an eternally successful franchise is the film industry's equivalent of the search for the Holy Grail: it might not even exist, but Hollywood is determined to continue trying to find the magic formula to make the dream a reality.
Few franchises in film history manage to keep up the momentum for too long. Perhaps only the James Bond series has succeeded in spanning several generations, and it has done so only by being entirely formulaic and predictable, only tweaking the raw components slightly over the decades of its existence. The Marvel Cinematic Universe has likewise managed to avoid running its course through a combination of careful world building, cross overs and the steady hand of producer Kevin Feige.
But for many other franchises the future isn't so rose-tinted. Sequels and prequels fail to capture the spark of the originals, concepts and storylines become over-worn and repetitious, and audiences become bored of the same old thing as franchise fatigue wears them down. In short, they forget what it was that made them great in the first place, transforming into bland commodities to be consumed like junk food.
From classic comic book characters who've lost their way some of the most iconic action movies of the 1980s, some franchises really need to return to their roots.