The annual San Diego Comic-Con is one of the biggest events in the U.S., where major studios announce plans for their big franchises and showcase previews of upcoming films.

This year, studios brought the biggest films to the event, with a number of stars making special appearances. "Batman v Superman: Dawn of Justice" showcased a sneak preview while Legendary announced its plans for a Skull Island film. Marvel showed off "The Avengers: Age of Ultron" and also announced the sequel to "Guardians of the Galaxy"; "Guardians," which were also screened to rave reviews.

Warner Bros. also showcased the last Hobbit movie and Daniel Radcliffe brought his latest film "Horns" to the convention. Some of the "Star Wars" cast also made a presence to promote the film.

The news of all these films excited fan boys and audiences alike, but it only emphasized a growing issue in the industry.

Half of these films will open in the summer while others will open in the holiday season, hoping to sky rocket at the box office.

However, this summer has seen a huge slump in blockbusters. Many of the biggest franchises have not garnered the expected box office results and some of them have even flopped.

What comes into question is the lack of originality in studios and their emphasis on franchises and sequels. For example, the announcement of "Skull Island" already had pundits speculating that yet another King Kong movie will be produced and it will most likely lead to yet another franchise. Warner Bros rebooted "Godzilla" and had extremely good results which may have influenced the decision for Skull Island. However, "Godzilla" had not had a movie since 1998 and that '98 film was universally trashed. Meanwhile, "King Kong" was recently produced in 2005. That movie, which had a $205 million budget, was a huge success critically and financially, and even won three Oscars. With less than 10 years having passed, it seems like a quick turnaround for the movie and that could easily lead to a flop similar to the latest "Spider-Man."

The same could be said of the upcoming "Batman v Superman" flick. On top of the fact that the movie is coming out the same day as "Captain America 3," Ben Affleck being cast as Batman may cause further backlash. "The Dark Knight" series ended in 2012 and only four years will have passed when the new DC film comes out. While this new film will include a number of iconic DC heroes, Batman fans may not want to see a new interpretation so soon, especially when the most recent films were so heavily adored.

One of the more interesting announcements, and one that furthers the notion of overindulgence from the studios, is the "Guardians of the Galaxy" sequel. The first film will be released in one week and it is still unknown how it will perform. And yet, there is already reportedly a sequel in the mix. This new series is highly unknown to comic book fans and while reviews are great, science fiction films can sometimes have trouble at the box office.

Marvel has had a solid track record for the most part and its films have over-performed. The question is how long will Marvel's success last before audiences get fatigued. "Transformers" seemed unstoppable, even with bad reviews. However, this year's installment underperformed and showcased the lack of interest by domestic audiences. The same could be said of "The Amazing Spider-Man 2." Few superheroes are more iconic that the web-slinger. But after five films, the movies seem to be grossing less and audiences are becoming less interested. Quality has a lot to do with both of these examples as neither "Transformers" or "Spider-Man" have become critical successes. But this furthers the idea that none of these cultural touchstones are completely invincible.

Comic-Con will always be one of the most fascinating events and will always bring fan boys. There is simply nothing better at generating excitement about upcoming projects and realizing cinematic dreams. But the question of whether studios will still be able to sustain the franchises and hope audiences will turn up for these films is prevalent, especially considering the current media landscape.