Rock on. How biopics are giving rock ’n’ roll new life.

There’s one movie this year that boasts more spandex than the upcoming “Avengers.” That dubious honor belongs to “The Dirt,” a Netflix biopic debuting today, about the heavy-metal band Mötley Crüe. It’s the first in a spate of rock-music movies that has Hollywood costume designers stocking up on denim, leather, and rhinestones. Credit the unprecedented success of “Bohemian Rhapsody.” Last year’s record-breaking, Oscar-winning biopic about Queen has Hollywood bullish on upcoming stories about Elton John, David Bowie, Céline Dion, Dusty Springfield, and Aretha Franklin.

Music biopics have been a regular fixture on screens since “The Jolson Story.” But the Mötley Crüe, Céline Dion, and Elton John movies are different from many past biopics. Like “Bohemian Rhapsody” and hip-hop group N.W.A.’s 2015 box-office hit “Straight Outta Compton,” these new projects are backed by the original artists. It’s an opportunity for the musicians to shape the narratives of how they’re remembered. There’s also another motivation: In the era of information overload in which decades-old music risks obscurity, biographical films can reintroduce classic music to younger listeners.

“Older generations [of musicians] aren’t making money from streaming. They’re getting up there in years and can’t tour like they used to, and the usual revenue streams to which they have become accustomed have dried up,” says David Browne, a senior writer at Rolling Stone magazine. “What do you do to keep music in the public eye and make a living? Biopics and jukebox musicals are the way to go.”

Queen knows how to play the game. In 2002, the monarchs of rock emulated the success of the ABBA musical “Mamma Mia!” by creating their own London West End production, “We Will Rock You.” Queen also followed the subsequent “Mamma Mia!” movie with “Bohemian Rhapsody,” named after their own song with a “mama mia” refrain of its own.

“Bohemian Rhapsody” not only earned $879 million worldwide – plus an Oscar for star Rami Malek – but its soundtrack album was a hit on Billlboard’s chart. In January, Queen briefly beat out Ariana Grande as Spotify’s No. 1 global artist. Even more astonishing? Seventy percent of those listeners were under age 35.

Aside from Queen, there’s virtually zero rock in Spotify’s current top 100 songs. Rock music is going the way of jazz, observers note, once too the vanguard of popular music. Artists from the ’60s and ’70s are already losing cultural purchase. Today’s radio defines “classic rock” as Nirvana and Pearl Jam. 

“The classic rock playlists are tightening up all the time and they are also shifting down a demographic,” says Matthew Wilkening, editor-in-chief of Ultimate Classic Rock, whose parent company, Town Square Media, owns 321 U.S. radio stations. “Something like two-thirds of the current airplay lists on classic rock is from the ’80s now. So these heritage bands, to some degree, are getting squeezed out.”

That explains why Alice Cooper wants a screenwriter to wrangle his life story (and pet python) into a “Bohemian Rhapsody”-style movie. Similarly, Elton John hopes that his self-produced “Rocketman” (starring Taron Egerton as the bespectacled and bejeweled pianist) will introduce a younger audience to “Goodbye Yellow Brick Road.” Like “Bohemian Rhapsody” and “Straight Outta Compton,” Elton John’s film takes significant liberties with facts and chronology. By contrast, Mötley Crüe’s “The Dirt” seems unvarnished. It chronicles the fallout from the band’s R-rated rock ’n’ roll-lifestyle excess.

“With these movies it’s controlling your future image for the rest of time,” says Chris Willman, features editor for Variety. “Not letting some biographer tell your story but finding a sympathetic screenwriter, director, and studio who will shape your story in a way that, 30 years from now, you’ll seem lovable and someone who triumphed over adversity.”

But for every artist that gets to tell their story the way they want – for example, the late Aretha Franklin handpicked singer Jennifer Hudson to star in the upcoming “Respect” – other biopics are unauthorized. Lynyrd Skynyrd unsuccessfully sued former drummer Artimus Pyle over “Street Survivors,” a story of the band’s tragic 1977 plane crash. “Stardust,” about David Bowie’s formative years, hasn’t received the blessing of the singer’s family. Without the rights to an artist’s music, biopics can flounder. When the Jimi Hendrix estate denied permission to “Jimi: All is By My Side,” the flop movie depicted the guitarist playing blues standards.

Michael Cieply, a former film producer, is familiar with such hurdles. He spent nine years on the Sony Studio lot trying to develop a music movie. “I invested a lot of that time in a United Artists project that was never made,” says Mr. Cieply, now executive editor for the movie trade publication Deadline. “It was a Merle Haggard project. What you learn is that there are extra layers of technical difficulty that mostly have to do with music rights. There are dozens of these pictures that people would love to make. There was a fabulous script floating around for 20 years by Tom Epperson and Billy Bob Thornton about Otis Redding. It was a perfect movie, but no one could ever quite get the music rights.” 

In an era of dwindling song royalties and falling album sales, music publishing companies may have extra incentive to assist such projects. They’re also licensing music to non-biopic movies built around artists’ back catalogs. For instance, this summer’s “Blinded by the Light” is about a British Muslim teenager who discovers Bruce Springsteen’s music. Director Danny Boyle’s “Yesterday” imagines a world in which no one remembers The Beatles – except for one wannabe singer-songwriter who re-creates the Fab Four’s songs and pretends they’re his own compositions. (Well, perhaps not "Ob-La-Di, Ob-La-Da.") 

Beyond that, expect a rush to develop biopics that emulate VH-1’s “Behind the Music” series, just as “Bohemian Rhapsody” did.

“It’s largely the same template,” says Mr. Willman. “It ends on a moment that leaves people feeling happy and wanting to go out and buy the catalog.”