What's behind the summer box office fizzle?

For Hollywood, the living hasn't been easy this summer as fewer people hit the movie theaters during the all-important July 4 holiday weekend.

According to Box Office Mojo, the top 12 movies earned $120.6 million during the Independence Day weekend, a 46 percent drop-off from last year and the worst performance during the holiday period since 1999. Overall, summer box office receipts are down 20 percent so far this year, according to Variety.

Paul Dergarabedian, senior media analyst at Rentrak, though isn't ready to throw in the towel on the summer movie season yet, arguing that upcoming releases such as "Dawn of the Planet of the Apes," "Guardians of the Galaxy," "The Purge: Anarchy" and "Lucy" should make up for the shortfall.

"The summer of 2014 was never pre-destined to rival the blockbuster record-breaking summer of 2013 which had a massive start with 'Iron Man 3' and included hits like 'Despicable Me 2,' 'Man of Steel,' 'Monsters University,' 'Fast and Furious 6,' 'Star Trek Into Darkness' and 'World War Z' to name a few," he writes in an email, adding that this "simply a more 'normal' summer."

"Of course there were several films that did not live up to expectations in the summer of 2014 (but that also happened last year with some big-budget, high profile failures but the hits outweighed the misses) and that made comparisons tough to such a strong lineup a year ago and thus the current steep percentage drop vs. summer 2013," he wrote.

Indeed, box office receipts hit a record $10.9 billion in 2013. That followed an impressive 2012 which had four films gross more than $1 billion.

Many critics have argued that the reason why movie theaters are ringing their registers less this year is that the films Hollywood studios are marketing aren't very good. Take "Transformers: Age of Extinction", which currently leads the box office. The feature has earned $175.4 million, far less than the other two "Transformers" movies, according to Box Office Mojo. Oscar-worthy, it apparently isn't. As Rene Rodriguez of the Miami Herald noted: "To say that Age of Extinction is the best installment in the money-minting Transformers franchise is like saying the best episode of The Love Boat was the one that had Charo in it: The praise is so faint, it's close to meaningless."

"Tammy", an R-rated comedy starring Melissa McCarthy, who gained notoriety from "Bridesmaids" and the sitcom "Mike and Molly", is another underperformer. Though the film, which was directed by McCarthy's husband Ben Falcone, opened in second place this past weekend, it's unlikely to become a juggernaut given its poor reviews such as the Washington Post's Anne Hornaday who noted: "'Tammy' is a bummer, not least because McCarthy's fans know she's better." Time Warner's Warner Bros. film studio, which released the film, not surprisingly was pleased by its performance, according to the Associated Press. Dergarabedian also noted that the film probably earned a profit given its modest production budget of $20 million and its $36 million in gross receipts as of yesterday.

Wall Street, which is used to the fickle taste of the American moviegoer, starts to worry about box office disasters when media companies take a charge against their earnings. Walt Disney (DIS), in particular had a string of box office disasters that required writedowns such as "Mars Needs Mom," a 2011 animated feature, 2012's sci-fi epic "John Carter" and last year's "The Lone Ranger," which starred Johnny Depp. Of course, the success of "Frozen", which has grossed more than $1 billion, has made investors forget about the string of failures, at least for now.