Speaking with Rolling Stone ahead of the May 31 premiere of FX's Sex Pistols biopic miniseries Pistol, Armstrong expressed agreement with the idea that punk rock — the real stuff — only lasted a few years in the late-'70s.
Everything punk-like that followed — including his own band — is a different thing "that has that Sex Pistols influence."
"Winterland  was the last Sex Pistols show, at least of the '70s, and I always say punk came to die in San Francisco, and the kids had to sort of pick up the pieces after that," the frontman said.
"The Sex Pistols killed punk before it had the opportunity to go mainstream back then. What they had proved is that punk rock was not meant for the masses. If you’re picking up the guitar to play punk rock music, it’s not for fame."
Armstrong and bandmates Mike Dirnt and Tre Cool were some of the kids who tried to pick up those pieces. Few would call Green Day a real punk band nowadays, but Armstrong says that was the original idea, of course.
Green Day even covered "Holidays in the Sun" during its early shows. He says the Sex Pistols' message of honesty (and anarchy) carried over to Green Day's early shows in the '80s.
"And obviously with Green Day it was a different trajectory altogether, but I gotta say I didn't predict that for us [laughs]."
Armstrong says the Sex Pistols' ethos still resonates today, and that's a good sign for music in the future.
"So when you get all of these pockets of kids all over the globe that are making music that has that Sex Pistols influence, who want to create their own underground form of anarchy, it gives you faith that music is not just there to be manufactured and corporate and consumerist," he concluded. "It’s there because people are investing into their lives and reflecting the way that they feel about the world and the way they feel about themselves. And that’s been the long legacy that the Sex Pistols left behind."