The Argentine-born filmmaker was one of studio boss Kevin Feige’s two top lieutenants alongside Louis D’Esposito: the trio had been working together since 2008’s Iron Man, a movie she co-produced. 

Yet the Marvel Cinematic Universe has seen interest wane ever since its spectacular success with the two-part Avengers: Infinity War saga.

After a poorly received Phase 4 that included some critical and commercial duds, the kick-off of MCU’s Phase 5 centered around a new villain, Kang the Conqueror, has disappointed at the box office.

Monday’s news from The Hollywood Reporter follows last week’s report from Business Insider that department heads at parent company Disney had until April to deliver CEO Bob Iger a list of 4,000 employees to be sacked.

“This is going to be an earthquake within Disney, because she was one of the high-level untouchables,” said Kamran Pasha, a screenwriter and media industry expert.

No reason was cited by THR for the departure, but a Disney spokesperson confirmed the news to the L.A. Times.

A representative for Marvel Entertainment could not be reached by Fortune for comment.

It’s unclear whether the departure of Alonso, who publicly clashed with Iger’s successor-turned-predecessor Bob Chapek in April over his stance on the controversial ‘Don’t say Gay’ bill, was voluntary.

But Disney expert Pasha believes it was an attempt by studio boss Feige to correct course after the recent spate of poor box office showings.

“If she can be guillotined like this without any warning,” said Pasha, “this is bigger news than I think a lot of people realize.”

Big-budget franchises under pressure

With the exception of blockbusters Spider-Man No Way Home—a Sony Pictures Entertainment film Marvel only co-produced—and Wakanda Forever, the MCU disappointed in Phase 4.

A chief complaint has been weak stories relying too heavily on subpar CGI special effects and lackluster characters that fail to resonate with the broad audiences Disney needs.

Heightening the crisis for Disney, the first Phase 5 film, Ant-Man & The Wasp: Quantumania, has underwhelmed at the box office. Now both Brie Larson’s The Marvels and a new Blade movie featuring Mahershala Ali have been delayed.

It’s not just the MCU that is faring poorly of late, however.

Big-budget franchises on a whole have been struggling, despite or perhaps because of every effort being made to keep milking their intellectual property regardless of artistic quality. 

DC’s rival superhero universe has been mostly a disappointment and is undergoing a hard reboot.

Disney’s Star Wars property is a shadow of itself, with a planned film from Lost creator Damon Lindelof uncertain and excitement over the third season of The Mandalorian has been subdued. 

The Harry Potter prequel series Fantastic Beasts was euthanized after a steady loss in box office receipts and the future of fictional superspy James Bond is up in the air after actor Daniel Craig’s departure.

Finally Amazon Prime’s big-money Lord of the Rings prequel series failed to garner a single nomination at the Golden Globes.

Arguably the most successful recent franchise entry was neither a theatrical film nor a TV series, but a video game. 

Hogwarts Legacy reaped $850 million in sales after just two weeks, according to Warner Bros. Discovery boss David Zaslav.

But Disney desperately needs results after promising in February to cut costs by $5.5 billion and thin out its workforce through 7,000 forced redundancies.