As I grew up, science fiction and action thrillers were always my favorite. The Star Trek series of films and movies with sequels, such as 2001 (which has a sequel 2010), Aliens (which had several sequels), and Predator (which also had several sequels) fascinated me, and they still do. Nowadays, I have enjoyed watching the X-Men series and Fast and Furious series of movies, so this current age of blockbuster films, increasingly dependent on prequels, sequels, and remakes (for a good article or two on this topic, Google "percentage of movies that are sequels"), fascinates me because of the following question. That is, how can sequels, prequels, and remakes continue to generate reasonably "new" content that audiences continue to pay to view? I think the explanations are several, including advancements in special effects (after all, how can Godzilla be remade so many times without improving special effects). However, I am beginning to notice new content generators, especially pertinent to prequels and sequels. Most notably, the two content generators that have really captured my attention are time travel and alternate vantage points, for which I would like to provide some examples.
In the case of time travel, I will focus on two movie sequels, Terminator: Genisys and X-Men: Days of Future Past (warning: some spoilers are contained in this paragraph). In the former film (only the trailer is currently available), events of the previous films of the Terminator series have changed the current timeline, so now a new "future" (i.e., plot content) has been created. In the X-Men film, Wolverine's consciousness has been altered in the past such that his past self has been made aware of future events. When the film has concluded, his actions in the past have changed the future (sound familiar) such that characters who were killed in previous films (e.g., Jean Grey aka Phoenix and Cyclops) are now alive again! (after all the timeline has been changed, so now new content can be generated). If the resurrection of dead characters does not validate time travel as an excellent magic eraser (so new content can be generated), I don't know what would!
As far as alternate vantage points, look no further than the Fast and Furious series. After watching Tokyo Drift, I was a little disappointed that Han died, and at the time, I simply chalked the events of this movie up as a closed thread. That is, nothing more would grow from this node of the story. Oh, how wrong I was, because at the end of Fast and Furious 6, an alternate vantage point is revealed to the audience! Han's killer, which we were unaware of in Tokyo Drift, was none other than Jason Statham, which fueled the audience's anticipation of an explosive thriller for the sequel Fast and Furious 7. In other words, the vantage point hidden from us in Tokyo Drift and only revealed to us in Fast and Furious 6, provided the content for the sequel.
I don't think anyone can argue that creativity is highly valued in Hollywood anymore, because more of each year's highest grossing films are now sequels or prequels than ever before. However, I do know that all wells, no matter how prolific, must run dry eventually, and all we can do is attempt to stave this off for as long as possible (or until we find new wells). In this case, time travel and alternate vantage points help Hollywood's wells from prematurely running dry. Moreover, I doubt this will change anytime soon, because from the investor's point of view (after all, from where does the financing for films come?), well-recognized series of movies, and their sequels, represent a fairly certain return on investment at a much lower risk than a completely original production. So the next time you watch a sequel, especially one that is part of a successful series of movies, watch for loose ends that have not been tied up (e.g., at the time, we didn't know who killed Han in Tokyo Drift). Who knows? You may just notice that one of the villains in a movie such as Captain America: The Winter Soldier, for example Frank Grillo's character, was badly burned but did not actually die!