Speaking to Time while on “The Fabelmans” press tour, Spielberg said, “My mom always referred to herself as Peter Pan, the little girl who never wanted to grow up. She loved being in our lives as our friend more than our mom. She befriended us more than parented us.” That’s true in the film too, where Mitzi is an eccentric who plays alongside her children and buys a pet monkey on a whim.
While Arnold/Burt was a computer engineer, Leah/Mitzi was a pianist. A filmmaker is both an artist and a technician; Spielberg/Sam inherited the skills of both his parents. Even so, Mitzi nurtures her son’s creative side more so than his practical father. While she didn’t live to see “The Fabelmans” (passing in 2017), Leah Adler actually encouraged her son to make an auto-biographical movie: “My mom was really kind of pushy about, ‘Steve, when are you going to tell our story? When are you going to tell my story?'”
Mother and son become estranged when Sam discovers Mitzi’s affair with Burt’s friend Bennie (Seth Rogen), while making a home movie for his mom no less. Sam has to keep the adultery a secret, and when Burt decides to hide the truth of the divorce from his children, Sam has to hide his knowledge.
“The Fabelmans” is not a condemnation though. Mitzi is prone to depression and simply happier around Bennie than Burt. There’s no bad guy, just two unfortunately incompatible people. Speaking to 60 Minutes, Spielberg admits he blamed the divorce on his father for many years, but if the movie’s any indication, he’s moved past that.