And moss grows fat on a rollin’ stone
This is an intentionally vague line meant to refer to Bob Dylan, as well as Buddy Holly.
Bob Dylan has a song called “Like a Rolling Stone” which addresses social injustice through the lens of the early 1960s. The next line of the song, “But that’s not how it used to be,” refers to the progress made by the Civil Rights Movement in addressing these injustices.
Buddy Holly quotes an English proverb in his song Early in the Morning which reads “a rolling stone gathers no moss.” Because Buddy Holly died at such a young age, McLean may have used the polar opposite of Holly’s original lyrics to reference his death by following it with “But that’s not how it used to be.”
At this point in the song, McLean transitions away from the three artists killed in the plane crash, and moves towards the artists who came after them.
Though the Rolling Stones may appear to be the obvious reference, when McLean uses his ‘rolling stone’ lyric he is referencing a time before the Rolling Stones became widely popular.
Additionally, it is likely a reference to Buddy Holly’s song “Early in the Morning”, which contains the lyrics “Well, you know a rolling stone don’t gather no moss”
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