Revisionist History
The Runaways were actually a very obscure late 70s band. I was in high school in those years, and I don't remember anybody ever listening to them. They were routinley trashed by critics as a no-talent gimmick act. As a punk act, they were laughed at. According to Wiki "The Runaways, though never a major success in the United States, became a sensation in 1977 in Japan thanks to the hit single "Cherry Bomb." Sounds a lot like "Spinal Tap"?
The fact is that some ex-members of the band had some MTV success in the 80s, otherwise, nobody would ever have heard of the Runaways. Hollywood is REALLY hard up for ideas when they make movies about bands that kind of a joke, 35 years ago.