I think I say somewhere in the book, while it’s not technically true that inside every great freeform progressive rock classic there’s a cheesy, easy listening cover version waiting to get out, it’s certainly true in this case.
The ‘this case’ he’s talking about is ‘Light My Fire‘ by The Doors. The Doors aren’t usually titled a progressive rock band, with Wikipedia preferring ‘Psychedelic Rock, Blues, Rock’, but I’ve always thought that some of their earlier lengthy classics like ‘The End‘ and ‘When the Music’s Over‘ were so close to progressive rock that splitting the difference would be impossible.
This was brought to mind as I was listening to Emerson Lake and Palmer‘s 1971 album Tarkus this morning. Except that the twenty minute long title track seems to me to have three or four ‘cheesy, easy listening cover version[s] waiting to get out’, and I love them all.