Fast-forward to this past weekend, when Transformers: The Last Knight, the fifth outing, posted a dismal five-day domestic debut of $69.1 million, including a Friday-Saturday gross of $45.3 million. Any which way the numbers are sliced, it is a franchise low. In June 2011, Transformers: Revenge of the Fallen commanded a massive $200.1 million in its five-day debut, followed by Transformers: Dark of the Moon's six-day haul of $180.7 million over the July Fourth corridor in 2011.

Transformers: Age of Extinction, a reboot of the franchise starring Mark Wahlberg instead of LeBeouf, opened to $100 million over the June 27-29 weekend in 2014 before topping out at $245 million domestically, compared with between $300 million and $400 million for the first three installments. At the same time, Age of Extinction became the first film in the franchise to cross the billion mark globally after earning $858.6 million overseas, including $320 million in China.

The Last Knight — which cost Paramount $217 million to make before marketing, according to the studio — is likewise faring far better overseas after opening to $196.3 million internationally from its first 40 markets. China made up the lion's share, or $123.4 million, although Hollywood studios only get back 25 percent of box-office returns from the Middle Kingdom, compared with 40 percent or so from most foreign markets. In North America, the return is closer to 50 percent, begging the question, "Is the international box office enough to ensure a film lands in the black?"

"It's all about risk versus reward and with mega-budget extravaganzas like Transformers. It truly is the international box office that can save the day and make the North American numbers less of a bitter pill to swallow for the studios," says analyst Paul Dergarabedian of comScore. "However, given the percentage of revenue that is actually gleaned by studios from markets like China, getting to the requisite profit margin can still prove challenging and make the justification for future installments difficult."

Paramount and partner Hasbro put The Last Knight's budget at $217 million before a major marketing spend.

The Last Knight isn't the first 2017 summer tentpole that has gotten a sunburn in North America before finding shade overseas. Disney's May tentpole Pirates of the Caribbean 5: Dead Men Tell No Tales, the fifth outing in the Johnny Depp series, won't earn much more than $175 million domestically, the worst of the franchise, while grossing more than $517 million to date internationally. Universal's The Mummy, starring Tom Cruise, has earned only $68.5 million in the U.S. since its release in early June, compared with $274 million offshore.

"The domestic sequel slump has officially turned into the sequel suck," says Jeff Bock of Exhibitor Relations. "The Transformers series needs a major attitude adjustment for it to work again domestically, which means an infusion of new talent from top to bottom. Paramount needs to do what Universal did for the Fast & Furious franchise when Dwayne Johnson and Jason Statham came aboard."

Bay has said The Last Knight will be his final Transformers film, but Paramount plans on keeping the franchise alive. Last year, the studio, then under the leadership of the late Brad Grey, announced three more Transformers movies, including a spinoff about the bot named Bumblebee that's set to hit theaters June 8, 2018.

It will now be up to newly installed Paramount chairman-CEO Jim Gianopulos to decide the fate of any chapters beyond the spinoff. The untitled Bumblee movie, starring Hailee Steinfeld and directed by Travis Knight, starts shooting later this summer and is said to be far cheaper than any of the previous films.

"U.S. audiences are not going to care about Bumblebee next year unless something changes," says Wall Street analyst Eric Handler of MKM Partners.

Megan Colligan, Paramount's president of marketing and distribution, says The Last Knight was always meant to be a global play: "You aren’t making the movie with just the U.S. in mind."