The whole Paul-Is-Dead controversy began in October, 1969 in Detroit. As I say in the introduction to my blog, I was a kid Beatles' fan among thousands of kid Beatles' fans in Detroit. We heard "Penny Lane" in 1967 (although I swear I heard that song in the fall of 1966. But that can't be, right?) We Beatles' fans knew something was wrong with that song. Paul's voice was not the same.
When Sgt. Pepper came out, alot of us did not like the music and the vibe that The Beatles were projecting, It was off, it was not right. So most of us kissed off Beatle fandom and became Monkees' fans.
So when the Paul-Is-Dead backmasked clues started surfacing, many of us thought it was a publicity stunt that The Beatles were using to--as they say in Detroit--"goose up" their sagging popularity.
As I started researching the changes in the members of the group, it occurred to me that--if there were heavy duty machinations with The Beatles--whoever surfaced among them would want some way to talk about it. Blurting it out publicly would have gotten band members replaced--and whatever consequences followed from that. So they hid their information in their songs.
The music industry is a fluid situation: musicians quit bands and join new ones; musicians hang out together; they listen to each others' music and the gossip they hear in recording studios. So I reasoned that other groups would want to share their information and gossip.
The results from testing songs backwards were 'way more than I expected: pop and rock musicians had bits of information about behind the scenes problems with The Beatles, and they shared their knowledge and gossip in backmasked songs.