The Simpsons… er… we mean… Figland is all over this book. So what makes it a symbol instead of just an ongoing gag or a plot device? It pretty much represents everything Jules envies in Ethan and Ash's life; Figland is symbolic of the golden opportunity that decides who ends up successful and who ends up struggling.
Ethan's show could just as easily have tanked, but it doesn't. He even has a spin-off that he calls "pretty lame," but "pushed […] through because [he] got delusional about the Figland brand" (14.135). It's the reason he and Ash have so much money, it's the reason they stay in New York, and it's (part of) the reason Jules fills up with jealousy every time she gets a Christmas card from them.
Figland is a symbol of the arbitrary fate that sometimes comes along for one person and not for the next—maybe it's because Ethan has great talent, or maybe it's because he just happened to be in the right place at the right time pitching his show to people who could put it on. No matter the reason, for Jules, it symbolizes everything she doesn't have—but maybe, just maybe, could have had if only she'd gone out with Ethan way back when.