“Time passes. That’s for sure,” reads the pithy Eileen Myles epigram that launches “Grandma,” Paul Weitz’s latest feature. Based on typical Hollywood fare, it could be hard to tell; unless one happens to be Meryl Streep or Richard Gere, life ends after 60, and if you happen to lack a Y chromosome it would seem to stop at least a decade earlier.

But some of this might be changing. “Grandma,” starring Lily Tomlin, 75, and Nancy Meyers’ “The Intern,” with Robert De Niro, 72, are making serious box office buck, drawing in audiences a third their age. Even odder is that neither film pivots around the trials of getting older or the fruits of late coupledom—rather, both focus on the relationships between those of a certain age and those considerably younger, part of a handful of recent movies eschewing traditional plots to tackle the tensions between traditionalists, baby boomers, Generations X, Y and Z.

Why the shift? Perhaps the fact that now more than ever we are likely to have to deal with those much older and younger than ourselves. Partly due to rising longevity and falling retirement rates, in 2015, for the first time in history, all five generations could potentially share a workspace. For those of Generations X, Y and Z, delayed marriage and childbearing means that it’s not uncommon for a single 32-year-old to socialize with those five to 10 years older, to compete for internships with applicants fresh out of college. We are entering an age of the pan-generational mashup, and we need to learn how to listen.

Many have dubbed “Grandma” another “abortion film,” in the spirit of “Obvious Child,” but the film’s real focus is on the clashes between the generations already born and blundering. “The gravity of the choice doesn’t elude us,” said Tomlin in an interview at the Sundance Film Festival—and in this film the gravity of the choice brings three generations of women together, quite literally, in a clinic waiting room. At the film’s start, Elle has just broken up with her much younger girlfriend Olivia (played by a very believable Judy Greer), and is soon after visited by her panicked granddaughter. The drama unfolds over the course of a single day, and throughout Tomlin wears her own clothing and drives her own 1955 Dodge Royal Lancer. It’s not surprising that Weitz wrote the role with only Tomlin in mind.