The end - or, at least, an end - is nigh for the Marvel Cinematic Universe, if studio president Kevin Feige's teases are anything to go by. But what could that actually mean in practice?
Talking to Collider, Feige suggested that, "as we get to [2018's Avengers] Infinity War there is a sense of a climax if not a conclusion to, by the time we're at untitled Avengers 4, the 22 movies that will have encompassed the first three phases of the MCU. And what happens after that will be very different. I don't know if it's Phase 4, it might be a new thing."
Elsewhere in the same interview, he says, "We have an idea [of what the MCU looks like post-Infinity War], and it's gonna be very, very different."
"Very, very different" could mean anything - an all-new lineup of heroes replacing the familiar faces entirely, a reboot from scratch with a different cast or something else equally dramatic, for example.
As a long-term comic book reader, however, it sounds very much like Marvel Studios is going to follow the same playbook that Marvel's comic book line has used for the last decade-plus, and use the oversized event storyline as an opportunity for a soft-reboot of its fictional universe.
The comic book arm of Marvel has used this formula for some years now, increasing in frequency as the need for sales bumps has grown. Events in the comic book universe would build to a particular peak, which would be characterized by one of a number of "event" series - 2008's Secret Invasion, say, or 2014's Secret Wars or the current Secret Empire (Marvel has a lot of secrets, apparently). The event would crescendo before the aftermath arrived with a cosmetic change in the status quo (SHIELD is now being led by a villain who's outlawed all superheroes! The universe has been recreated and reality is subtly different as a result!) and a branding that could be used to promote the line in stores as a new beginning, using titles like "All-New All-Different Marvel" or "Marvel NOW!"
Infinity War could be a movie that offers the same opportunity for Marvel's movie universe. Depending on the outcome of the movie, it's possible that it - and the untitled fourth Avengers movie, the very title of which is a spoiler, Feige told CinemaBlend - could create an altered status quo for the Marvel Cinematic Universe moving forward that doesn't require any more of a linewide shift than Captain America: The Winter Soldier or even Captain America: Civil War (the end of SHIELD and the end of the Avengers, respectively), but could nonetheless be used to promote a "new beginning" for the studio.
Arguably, it would need that kind of boost by that point; "Phase 4" just doesn't sound as impressive as Phases 1 through 3, and by 2019, Marvel Studios will have been producing movies for more than a decade - an ideal time to freshen things up, even if it's merely with a temporary coat of paint.
Those imagining that the post-Infinity War changes will be anything more than cosmetic are likely fooling themselves; if nothing else, the existence of a third Guardians of the Galaxy and second Spider-Man would appear to confirm no reboot plans, in addition to making it even more obvious that the Earth is going to survive the showdown with Thanos. Instead, imagine a more metatextual shift towards actors and characters still under contract, with even the crown jewel of the franchise reflecting that change.
Perhaps Avengers 4's title is under wraps because it pulls from a very popular branch of the comic book version of the franchise. After all, is there any hardcore Marvel fan who wouldn't get excited showing up at the theater to see The New Avengers?