You'd think the folks at Fox would be going bananas over the box office victory this weekend for "War for the Planet of the Apes."

After all, this was supposed to be the first truly close competition of the summer, with "War" battling the still-strong second weekend of "Spider-Man: Homecoming." In the end, however, "War" was far and away the winner, earning an estimated $56.5 million -- slightly-less than what was projected -- while Spidey also fell behind expectations with an estimated $45.2 million

And yet, by the franchise's own standards, it's hard not to see "War" as a disappointment. It opened in more theaters than the first two films in the prequel trilogy, 2011's "Rise of the Planet of the Apes" and 2014's "Dawn of the Planet of the Apes." Still, it opened well below "Dawn" (which debuted with $72.6 million) and barely a hair above "Rise" (which premiered with $54.8 million). It was also riding good reviews (95 percent at Rotten Tomatoes) and excellent word-of-mouth (it earned an A- at CinemaScore, just like the two previous "Apes" films).

Domestically, "War" could well end up the lowest grossing of the current "Apes" trilogy," failing to beat the $208.5 million "Dawn" earned in North America or even the $176.8 million that "Rise" earned here. Plus, the movie cost $150 million to make. For Fox to earn a profit, after production costs, marketing costs, and the theater owners' share of ticket sales, "War" will have to earn about $600 million worldwide, so its global gross of $102.5 million so far suggests that breaking even will be a long shot. How did this happen? Here are a few reasons to factor in:

1. Superheroes > Apes
Even with the disappointments this summer of such sequels as "Pirates of the Caribbean: Dead Men Tell No Tales," "Transformers: The Last Knight," and "Despicable Me 3," Hollywood's shrugging assessment that moviegoers were suffering from franchise fatigue rang hollow. After all, these films earned terrible reviews and weak word-of-mouth. Some franchise movies with good reviews and positive word-of-mouth were succeeding, like "Guardians of the Galaxy Vol. 2," "Wonder Woman," and "Spider-Man: Homecoming."

But what if it was just that these movies all featured DC and Marvel comic book heroes? Individual moviegoers may claim to be getting tired of superheroes, but as a group, we still flock to see them, even when the movies earn terrible buzz, like "Batman v Superman: Dawn of Justice" and "Suicide Squad." Maybe what "War" needed was an ape with a cape.

2. Rotten Tomatoes Scores Matter to a Point
The studios have been complaining all summer that poor scores at RT have been discouraging customers, especially since those scores appear right in front of the virtual box office window at Fandango. As this column noted last week, there is some research that suggests that weak RT scores do affect online buzz. However, that research also showed that high RT scores do little to improve buzz. Which means, as good as the reviews were for "War," they didn't really help sell tickets.

3. "War" Looked Too Much Like "Dawn"
Conventional Hollywood wisdom has it that mass audiences want to see something familiar and comforting. That's the logic behind having so many reboots, remakes, sequels, and universe-building films, and it's the reason why so many sequels seem to deliver the same experience as previous installments. If there really is franchise fatigue, this is what causes it, and it's one reason why audiences responded so well to "Wonder Woman" and "Spider-Man: Homecoming": even though they told familiar stories, they felt fresh and different in their approaches.

Looking at the trailers for "War," however, its scenes of gorilla guerrilla warfare looked a lot like those of "Dawn." Also, if you think about it, "War" is not just the third movie in a trilogy that started six years ago; it's the ninth movie in a franchise that's been around for 49 years and which also included multiple spinoffs in other media.

Ticket buyers who saw "War" seem to have enjoyed it as much as they did the last two movies, but to get them into the theater, the film's marketing needed to do a better job of convincing those moviegoers that "War" was not something they'd seen before.

4. Star Power Still Means Something
Used to be that Hollywood valued movie stars for their ability to sell tickets. Now, however, what matters is their ability to get likes on Instagram and Facebook.

Social media buzz is increasingly crucial to a film's success, and that means casting stars with big online followings. Woody Harrelson, "War"'s most recognizable face, may have been a familiar face to moviegoers and TV viewers for more than 30 years, and he may have boosted his profile recently by co-starring in the huge "Hunger Games" franchise, but he doesn't have much of a social media game. Neither does Steve Zahn, who plays a prominent new ape character. Andy Serkis, who has played the lead role of chimpanzee Caesar in all three of the recent "Apes" films, does have a solid Twitter following, but it seems not to have been enough.

5. Timing Is a Big Deal
"Homecoming" may have settled for second place this weekend, and it may have taken a bigger second-week hit than expected, tumbling 61 percent from last weekend's premiere. Still, Spidey proved a formidable adversary to Caesar.

Pre-sales for the two movies on Fandango were neck-and-neck, with "Homecoming" just a nose ahead of "War." Indeed, "War" had to fight off a lot of still-strong movies that targeted similar viewers. Action fans also had "Homecoming," "Baby Driver," and "Wonder Woman" as options. Older viewers who might have appreciated "War"'s philosophizing and nostalgia value, may have been drawn to critical darlings "Baby Driver" and "The Big Sick." And women may have turned toward the romantic comedy of "The Big Sick" or the horror of new release "Wish Upon."

By contrast, "Dawn" had little serious competition when it opened on this same weekend three years ago -- just the third week of "Transformers: Age of Extinction" and the second week of "Tammy." Neither film earned more than $17 million that weekend, giving "Dawn" an easy ride to its $72.6 million premiere.

But it's not just movies that have already opened that are rivals to "War." After all, next weekend sees the releases of "Dunkirk," "Girls Trip," and "Valerian and the City of a Thousand Planets." One is a Christopher Nolan action epic, the sort of movie that demands to be seen on the big screen and that attracts adults of all ages. One is a comedy that targets women and African-American viewers. And one is a sci-fi wild card from "Fifth Element" and "Lucy" director Luc Besson. As audiences flock to "Dunkirk" and "Girls Trip," "War" could have a tough time staving off erosion during its second weekend.

6. Can't Always Count on International Markets
It's still possible that overseas moviegoers could rescue "War," the way they have so many other domestic underperformers this year, and the way they did the last two "Apes" movies, which earned between 63 and 70 percent of their total grosses abroad.

So far, however, "War" has earned just 45 percent of its total overseas. That share may well improve over the coming weeks. Still, the film's foreign grosses will have to be about ten times what they are now in order to make a profit, and that's unlikely.

As "Transformers: The Last Knight," "The Mummy," and "Baywatch" have all demonstrated this summer, you can make the lion's share of your money overseas and still not turn a profit. Writing off the domestic audience is leaving money on the table. As "War" has shown by premiering $17.1 million below "Dawn," every American ticket dollar is worth fighting for.