As the culmination to more than a decade of innovative franchise filmmaking, Avengers: Endgame serves not only as a capstone to the story that began with 2008's Iron Man—the first film in what became known as the Marvel Cinematic Universe (MCU)—but as a testament to the power, and profitability, of big-screen serialization.
In the years before Marvel started making feature films in-house, blockbusters, including superhero movies, might have sequels, but each one was expected to stand on its own as a complete, independent cinematic experience. Plotlines were wrapped up at the end of every movie, and characters rarely crossed over from one franchise to another.
The MCU, in contrast, was built on the same storytelling principles that ruled in Marvel's four-color comic books: serialization, crossovers, and reasonably consistent universe-wide continuity, all of which created incentives for fans to branch out from one hero to another, following not just a single character and story but an entire universe of them.
This strategy was initially viewed as risky, since an interlinked story might be confusing, or widely disliked, and thus drag the whole franchise down. Instead, when the MCU's initial group of heroes teamed up in 2012 for The Avengers, it proved more successful than almost anyone imagined. This reshaped Hollywood, with cinematic franchises from DC Comics to Transformers seeking to establish interconnected universes of their own.
Few succeeded as Marvel did—Endgame grossed more than $1.2 billion globally on its opening weekend, breaking just about every box office record imaginable—but Hollywood learned a lesson anyway: In the internet era, no storyline is too complex for dedicated fans. That goes for Endgame's knotty, referential storyline, which serves as a well-earned review of the franchise's high points and a round of self-congratulation at the project's success. It feels like a grand finale, but don't expect it to be over: Marvel's cinematic endgame is to always have another story to tell.