Unlike Bob’s Burgers. While Bob Belcher and his quirky family haven’t been around for anywhere near as long, both shows had already established huge casts by the time they made the jump from small screen to the big screen.
Despite this, The Simpsons Movie (unlike The Bob’s Burgers Movie) introduced new characters during the setup of its complicated, ambitious plot. The Simpsons Movie's story was, like an episode of the series, effectively split into three sub-stories involving Homer adopting a pig, Springfield being quarantined by the government, and the Simpsons escaping to Alaska before returning to save the day. This complex plot involved the introduction of a new villain, which meant dedicating screentime to an unestablished newcomer despite the film's already busy plots.
The Simpsons Movie needed to invent a new character so that the entirety of the show’s sprawling cast could be united against a bigger, external evil. However, as funny as Albert Brooks’ Russ Cargill was, he did feel like an imitation of Hank Scorpio and a pretty one-note character. Unlike The Simpsons Movie, The Bob’s Burgers Movie avoided this issue by making an existing minor character, David Wain’s Grover Fischoeder, its villain. This meant that the animated movie could cut the character from future episodes—since he will be in prison—without affecting the status quo of Bob’s Burgers week-to-week. Thus, no screen time was wasted on introducing new characters and The Bob’s Burgers Movie’s story felt tighter than The Simpsons Movie’s more ambitious plot.
Why The Bob’s Burgers Movie Didn’t Need A New Villain
In fairness to The Simpsons Movie, it was always going to feature a bigger story than The Bob’s Burgers Movie. The fact that Spider-pig became a major meme before The Simpsons Movie was even released proves that The Simpsons still held on to some of the show's status as a legendary piece of iconic pop culture by the movie’s 2007 release. As such, The Simpsons Movie was a major, highly-hyped blockbuster event in a way that The Bob’s Burgers Movie was never intended to be. The Bob’s Burgers Movie could pull off a more modest murder mystery story precisely because the sizable fandom of Bob’s Burgers wasn't expecting anything quite as elaborate as The Simpsons Movie’s massive cross-country adventure.
While both movies did end up feeling like extended episodes of their respective TV shows, The Bob’s Burgers Movie didn’t need a new villain because the source show is a smaller, more grounded comedy. As the surreal “jockeys are secretly a fantasy race of magical elves who live underground” plot of The Simpsons episode “Saddlesore Galactica” alone proves, the show has always been a stranger, more ambitious, and altogether bigger beast. During the peak of its popularity, this led to much of the critical acclaim enjoyed by The Simpsons. However, when it came time to make a theatrical spinoff, this same tonal disparity meant that The Simpsons Movie needed a new, big-picture villain for its huge story where The Bob’s Burgers Movie could tell a smaller story with its existing cast.