While fans are still sad that Marvel's Agent Carter is gone, and Marvel itself hoped the show would go on longer, the call ultimately came down to ABC, and series star Hayley Atwell is pretty sure she knows why they ended it.
During an interview with The AV Club, Atwell said that her next project, the legal drama Conviction, probably seemed like it had more upside for ABC.
"It’s a shame the network canceled it and wanted to put me in something more mainstream," Atwell said. "You know, Marvel didn’t want it to end. There’s lots of online campaigns to bring her back. Fans loved her. I think it was just a network economical thing: 'Let’s put Hayley Atwell in something more mainstream that’s less genre-specific and see if we can get higher ratings.' And unfortunately, that isn’t, as an actor, anything I’ve got control over. But maybe, in small ways, characters like Peggy Carter very slowly pave the way for it to be possible for other female-led narratives to exist."
The series, which spun Steve Rogers's wildly popular love interest from Captain America: The First Avenger off into her own adventures, ran for two seasons. It dealt with the founding of SHIELD, Carter's evolving friendship with Iron Man's father, and more.
Around the time of Agent Carter's cancellation, Marvel killed both Peggy Carter (in the present day, as an old woman) and Howard Stark (in flashback) in Captain America: Civil War.
In the time since, Atwell has been open about her continued interest in revisiting the character, who could plausibly appear in filler material set before the Marvel Cinematic Universe's 2008 launch. She was one of a number of characters rumored to be under consideration for an appearance in Captain Marvel, which is set in the '90s, although there has been no indication that Atwell has been cast or that more Peggy Carter is anything besides fan hopes and rumors at this point.
Fans can still see Marvel's Agent Carter with a Hulu subscription, or buy episodes on various other streaming platforms. Unlike other Marvel Cinematic Universe-tied TV series, it is not currently on Netflix.