Trying to craft a buddy film about gentrification is a lot like making an action movie about global warming. While inherently dramatic, both processes happen so slowly, audiences are liable to lose interest while waiting for the ice caps to melt. And so it goes with “The Last Black Man in San Francisco,” a gorgeous and touchingly idealistic movie centered on a young man who refuses to give up on the dream of one day moving back into his childhood home — a stunning Victorian building that he still visits roughly every other week, sneaking onto the property to touch up the exterior paint or tend the garden, even though a white couple have been living there for years.

A collaboration between Bay Area best friends Joe Talbot (who directs) and Jimmie Fails (who plays the title character, also named Jimmie), the promising pair’s first feature — following Sundance-christened short “American Paradise” — crafts a lovely space in which to spend two hours, but lacks the kind of dramatic motor that might compel folks to invest in a man who spends his days skateboarding around a city where he can barely afford to live. “You never really own sh—,” a bystander says at one point, surveying the smoking remains of a rent-controlled apartment building as he studies the white man in the fluorescent orange construction vest playing gatekeeper.

Back in the ’40s, when Jimmie’s grandfather moved into San Francisco’s historically black Fillmore District, African-Americans couldn’t own property in most areas of the city. For years, the Fillmore was shared by black and Japanese-American families, until the latter were rounded up and sent to internment camps during World War II. It’s not a proud moment in the nation’s past, but it gave rise to a sense of black community in the neighborhood, which came to be dubbed “Harlem West” — and which has since become a desirable spot for affluent white homeowners.

As a child, Jimmie spent the first half of his first decade living in a beautiful two-story mansion off Golden Gate Avenue in the Fillmore, having the run of a house his grandfather built. At least, that’s how Jimmie remembers it, although one look at the building — with its hard-carved details, fish-scale shingles, and witch’s hat turret — suggests that it was erected a century earlier than the family legend maintains. In any case, something went wrong, and everyone split up, scattered to different corners of the city. Hit hardest, Jimmie spent at least a year in a group home and another stretch sleeping in a big banana-yellow car.

Lately, Jimmie’s been living with his best friend Mont (Jonathan Majors) and his invalid dad (Danny Glover), fixating on one day reclaiming that old house — which must be worth about $4 million now. That’s way too expensive for Jimmie, who works as a nurse in an elder care home. Meanwhile, Mont is a gifted artist and an aspiring playwright who in his day job sells fish to white people.

Caucasians, when we see them in the film, are presented like some kind of bothersome fungus: At first, a few spores come in, and the next thing you know, they’re shopping for organic produce, talking too loudly, and acting like they own the place — whereas Jimmie can barely afford to pay rent. One night, stretched out on the floor beside Mont’s bed staring at the ceiling, Jimmie wonders aloud whether the new owners of his old house might allow him to move in and live as “a caretaker” — a proposal that’s almost as pathetic as a lovestruck teen suggesting to his dream girl that he doesn’t expect her to return his affections and would settle for being her butler for life.

And then, as if by some miracle, Jimmie happens to see the former residents packing up their things. After checking with a local Realtor — who, as a white guy, will predictably wind up trying to steal the house out from under our hero — Jimmie hatches a plan to swoop in and claim it as his own: He rounds up a bunch of heirloom furniture from his aunt’s garage, moves in, and calls the gas company to switch the bill to his name.

It’s an outrageous scheme, but Jimmie is such a likable fellow that we might well root for him to get his wish. Squatter’s rights are a real thing in the state of California, although it might have helped for the movie to explain how Jimmie thought he would be able to claim them. Typically, the new tenant must occupy the property and pay taxes on it for no less than five years. While Jimmie and Mont have a magical kind of chemistry in the film — which is as much about friendship as it is about the injustice of property ownership — five years is a long time to watch them wallow.

Even though race relations, the class struggle, and gentrification are not only worthy but essential themes in contemporary drama, audiences tend to tune out when those issues are thrust front and center as plot. The Brazilian film “Aquarius” tried it a few years back, but in that case, it gave us a movie star (Sônia Braga) and a dynamic storyline about fighting a greedy land developer. “Last Black Man” is more of a mood piece, leaning on DP Adam Newport-Berra’s radiant cinematography and the vibrant swells of Emile Mosseri’s score to sustain our warm feeling toward its two characters.

The film was supported by the folks at Cinereach, who have demonstrated over a series of outsider projects — ranging from “Beasts of the Southern Wild” to “The Florida Project” to “We the Animals” — that an investment in sound and visuals can elevate unrefined personal visions into something art-house audiences take seriously. Building upon that strategy/shtick, “Last Black Man” looks and sounds great. And yet, while Talbot and Fails claim to have walk-and-talked their way all over San Francisco, the script — and especially the dialogue — is the most disappointing element of their first feature.

Compared with “Sorry to Bother You” or “Blindspotting” — a pair of loquacious, hyper-literate Oakland-set indies that premiered a year earlier at Sundance — “Last Black Man” has a relatively laid-back feel. Talbot, who is white, has a personal connection to both the city and his best-friend star. But unless we already know the Bay Area well, it’s hard to appreciate the unique kind of ennui that’s eating away at these fiercely loyal friends — and virtually impossible to accept the downbeat denouement that follows the film’s underwhelming climax: a play in which Mont drops a bombshell that should have been obvious from the get-go.

In a strange way, the film feels like an unconventional romance, where our hero is obsessed not with a person but a house. It’s too late to give notes, and yet the central friendship robs the film of the dynamic it needs. As one possible solution, had Talbot switched up the dynamic and rewritten Mont as a female character, we might have found ourselves in a potentially interesting ménage à trois, where Jimmie is forced to decide which matters more: the woman he loves or the only house he’s ever wanted to own — and then the realization that you can never truly possess a person or a home, and that neither truly defines you, would have resonated more.