It turns out Sony's Spider-Man deal with Marvel Studios secretly fell apart well before the general public was made aware.
The Sony/Marvel split actually happened "about three-quarters of the way through" post-production on 2019's Spider-Man: Far From Home, as detailed in Tara Bennett and Paul Terry's book, The Story of Marvel Studios: The Making of the Marvel Cinematic Universe. "There were only a handful of us that were aware of that -- we didn't tell the filmmakers [or] the actors," explained Marvel Studios President/Chief Creative Officer Kevin Feige. "We didn't want it to color the finishing of the movie or the press junket. All I cared about was finishing the movie to make it feel as great as we could."
Marvel and Sony announced their plans to bring Spider-Man into the Marvel Cinematic Universe in February 2015. Tom Holland was officially cast as the MCU's Peter Parker the following June and made his debut as the character in 2016's Captain America: Civil War, prior to starring in the MCU's first solo Spidey film, Spider-Man: Homecoming, a year later. Holland was only coming off reprising his role in Far From Home when news of the Marvel/Sony split broke in August 2019, throwing his future as the web-slinger into doubt.
After Holland put increased pressure on both studios to reach an agreement, Sony and Marvel announced they had settled on a new deal to share the Spider-Man movie rights near the end of September 2019. Holland has since confirmed he "was a part of a few phone calls during that process," adding that he doesn't anticipate a similar situation happening in the future. "I think they found a way in which it can be beneficial for both studios, and I'm just kind of like a kid in the middle of it, between two parents during an argument," as he put it earlier this year.
The actor is reprising his role as Peter Parker in Spider-Man: No Way Home, a film that pairs the web-slinger with Doctor Strange (Benedict Cumberbatch) on a multiversal adventure that reportedly features multiple villains from Sony's non-MCU Spider-Man movies. "We were all treating [No Way Home] as the end of a franchise, let's say," said Holland in a recent interview. "I think if we were lucky enough to dive into these characters again, you'd be seeing a very different version."
Spider-Man: No Way Home arrives in theaters Dec. 17.
Source: The Story of Marvel Studios: The Making of the Marvel Cinematic Universe, via ComicBook.com