Partway through this new Questlove documentary about Sly Stone, his band, the Family Stone, and the joyous, urgent funk they made, I got a little sad. Not for Stone, per se, and not for fame’s warping effect on his personality and relationships or for the serious drug addiction that maybe helped him cope with being that recognizable. (If “psychedelia” was a look, he looked it: piles of hair often cherried by a hat; capes, tight leather and denim; shirts, vests and jackets that never ever seemed to close.) I got sad because I could predict the notes the movie would hit — collapses, breakups, recriminations, redemption.

I could make that prediction because of all the “Behind the Music” I’ve watched. This movie, “Sly Lives!,” tells Stone’s life as one of those “... and then it all fell apart” stories. Ahmir Thompson, the director better known as Questlove, proceeds with more care — with ardor even — than that series, which ran for about 17 years on VH1 and developed a formula that itself became an addictive experience. You don’t know “binge watch” until you’ve lost an entire day on that show’s roller coaster.

“Sly Lives!,” which is streaming on Hulu, traces the arc of a vital career, and down is where, for a time, it led. Stone is an artist partly responsible for making “too much, too fast,” in the rock ‘n’ roll universe, feel inevitable now. And if George Clinton happens to surprise you with the news that he and Stone had been using crack and were arrested in 1981 for possession, withholding that discovery constitutes minor cultural malpractice. Yet how does a filmmaker devise an alternative to the old rise-before-demise template? Failing that, how does a filmmaker enliven the journalism of the format with insight, feeling, personality, an argument?

Questlove would like “Sly Lives!” to brush the dust from Stone’s pop pedestal, to celebrate his music as sui generis polymathic synthesis and as hip-hop’s bedrock, to imply that his ethos, zeal, caution and nerve persist in his scores of studio-wizard and rhythm-vision progeny: for starters, Stevie Wonder, Prince, Lenny Kravitz, Outkast, Erykah Badu, Meshell Ndegeocello, LCD Soundsystem, Kendrick Lamar, Childish Gambino, Steve Lacy. But the movie gets lost in the gulf between standard, if illuminating, biography and roiling existential crisis.

For “Sly Lives!” is a title with freight. “The Burden of Black Genius” is what follows in a parenthetical, but “Black” gets a strikethrough.

The film opens with its director asking for a definition of “Black genius” from Clinton, D’Angelo, Chaka Khan, Q-Tip, Nile Rodgers, Jimmy Jam, Terry Lewis and guitarist Vernon Reid. Thought bubbles ensue. André 3000’s endorsement of Black genius as a phenomenon he loves “when it happens” is as near an answer as anyone gets. And Stone, who’s 81 now, evidently couldn’t be cajoled into comment.

He was born Sylvester Stewart and reared in Vallejo, California. His musical life began in the church and was fortified by playing records on the radio station KSOL and producing songs for other Bay Area acts at Autumn Records. He stopped studying music in college and, in 1966, formed a band of his own with his siblings, Rose (keys) and Freddie (guitar), alongside Cynthia Robinson (trumpet), Jerry Martini (sax), Greg Errico (drums) and Larry Graham (bass).

These people found one another at the civil rights movement’s apogee, and their septet — Black and white, men and women — was a union that advertised integration’s frictionless possibility. No band had ever sounded as much like rubber, as sprung, tight, aimed. They were signed to Epic Records. And by 1970, four albums and a pile of inescapable, inventive, deeply grooved songs — “I Want to Take You Higher,” “Everyday People,” “Thank You (Falettinme Be Mice Elf Agin)” to name but three — had made them stars.

Every morsel of archival material weighs something: the clips from Ed Sullivan and Dick Cavett’s TV shows, the images and outtakes from the group’s recording sessions, the images that accompany the scholar Mark Anthony Neal’s on-camera invocation of late ’60s national turmoil, the band’s chemically enhanced set at Woodstock, Stone’s publicity-stunt wedding at Madison Square Garden in 1974, the news reports of his many drug arrests.

An old TV interview that finds Stone ruminating on fame’s leeward side provides the meatiest of that material. But after an hour of this, you’re tired. Dexterous montage keeps being passed off as exploratory depth.