In the introduction to the Collected Edition of Crisis on Infinite Earths, Crisis writer Marv Wolfman refers to a letter he received from a fan when he was writing Green Lantern which asked about a continuity mix-up. He writes:
The letter to GREEN LANTERN made me wonder how DC could simplify its continuity and lure new readers to the fold. Suddenly I thought of The Monitor and my original intent for the character … The ideas evolved quickly, and within four days DC approved a complete revamping of their entire universe
and the rest was pretty much history.
The Green Lantern issue was #143 cover dated August 1981 and, as I happen to own that issue, I thought I’d track down the letter:
And Marv’s response:
The important bit (at least from the point of view of Crisis) is this:
I’m still not sure I buy the idea that “though old-time readers had no problem understanding DC continuity, it proved off-putting to the new readers” – if kids reading about parallel Earths in the 60s and 70s could keep it straight in their heads, why were kids in the 80s any different?
Still, thanks to Gary Thompson for staring Marv and the others down the path they eventually went along.