Despite the trilogy's success, Sam Raimi's Spider-Man 4 never went beyond the development stage. Sam Raimi's Spider-Man and Spider-Man 2 were massive hits not only as trailblazers in today's golden age of superhero movies but also as self-contained blockbusters. Logically, expectations were high for future sequels, starting with the overly ambitious Spider-Man 3, which included Spider-Man's symbiote suit, Venom, Sandman, and Harry Osborn's New Goblin. Spider-Man 3's lower audience and critical reception put the franchise's future in jeopardy, but that didn't stop Sony from planning more sequels.
Although Sam Raimi wasn't fully satisfied with Spider-Man 3, he agreed to work on Spider-Man 4. Raimi wanted to tackle Vulture and Felicia Hardy, who would have moonlighted as either Black Cat or Vultress. But despite having Zodiac writer James Vanderbilt on script duties, John Malkovich as Vulture, and Anne Hathaway as Felicia Hardy — as well as storyboards and costume tests — Sam Raimi determined that he wouldn't be able to deliver a movie he would be proud of, saying "I couldn't get the script together in time, due to my own failings, and I said to Sony, ‘I don't want to make a movie that is less than great, so I think we shouldn't make this picture" (via Vulture). After devoting several years exclusively to directing the Spider-Man franchise, scrapping the fourth film allowed Sam Raimi to take on fresh creative projects.
Why Sony Chose To Reboot The Spider-Man Franchise
Since Spider-Man 3's negative reception was a clear sign that Sam Raimi's Spider-Man franchise wasn't infallible, Sony already had solid plans for a Spider-Man reboot even before Spider-Man 4 was canceled. Sam Raimi's exit from Spider-Man 4 only confirmed to Sony that it was time to start from scratch, and they didn't hesitate, jumping straight into development on The Amazing Spider-Man as soon as Spider-Man 4 was officially scrapped. Besides, Tobey Maguire and the rest of the cast were also closely tied to Raimi's project, therefore Sony wouldn't have been able to continue the same story without the original cast fully onboard.
The Amazing Spider-Man and its sequel explored parts of Peter Parker's mythos that Sam Raimi's franchise couldn't or wouldn't, like Peter's genuine love for Gwen Stacy and the mystery of his parents' deaths. Although not as successful as Sam Raimi's trilogy or Tom Holland's MCU Spider-Man, Marc Webb's The Amazing Spider-Man duology delivered a fresh take on the wall-crawler and his world. Oscorp, the Lizard, Electro, Spider-Man's homemade web-shooters, Peter Parker's agility and humor, Andrew Garfield's performance and chemistry with Emma Stone, and the two films' breathtaking web-slinging scenes are only some of The Amazing Spider-Man highlights that helped Sony's reboot stand out from other live-action Spider-Man adaptions.
Could Spider-Man 4 Still Happen?
Andrew Garfield and Tom Holland's Spider-Men seemed to have buried the possibility of Sam Raimi's Spider-Man 4 for good. But the return of the two previous Spider-Men and their respective villains in Spider-Man: No Way Home has given the canceled project another chance at life. So, now that all three live-action Spider-Men are part of the same multiverse, the possibility of another Tobey Maguire appearance as Spider-Man is kept on the table.
However, a full-fledged Spider-Man 4 is rather unlikely. Sam Raimi and the main cast's schedules would have to align, and Marvel Studios would have to allow Sony to make a Spider-Man movie not directly connected with the MCU's main universe and its characters, which goes against the deal that has made Tom Holland's Spider-Man so successful. As such, the most likely way to see Tobey Maguire back as Spider-Man is in another MCU multiversal event centered around Spider-Man or in a franchise-wide crossover like the upcoming Avengers: Secret Wars.