Who knows? All I can say for sure is that a seven-page script was created titled "The Marvel Age of Comics: 15 Minute History in Film," one that explained how, starting in 1961, Stan Lee changed everything. The film was meant to be narrated by Stan himself, who can be seen in sketch form on the first page of the script below.
The artist for that six-panel intro? None other than Stan's baby brother Larry Lieber, who also happened to script the introductory appearances of both Iron Man and Thor.
[Click to view any of these pages at a larger size.]
There's plenty of interesting info here, especially when Stan explains the creation of two of Marvel's most important properties.
One the first of the pages below, Stan details how the Fantastic Four were born: "Then I got together with Jack Kirby and we came up with the idea that was to be the cornerstone of many projects to come. ... " (Emphasis on the word "we" is mine alone.)
One the second page below, Stan then tells how Spider-Man was created: "I knew this was the right direction and we had to have more ... I went back to work, this time with a great artist by the name of Steve Ditko. Working for many a feverish day and night, slowly the ideas came together ... " Unfortunately, the admission of the collaborative nature of the creation isn't quite as clear as with the F.F. history.
Read the script for more details on the past and (then) future of Marvel Comics.
Was this ever filmed? Not that I'm aware of. But whether it was or not, the script alone is an interesting artifact of how Marvel saw itself in 1978.
But my personal favorite part of the script is the handwritten note scribbled near the bottom of the first typed page above:
"Clean up Bullpen"
If you were there, you'd know that was impossible. The Bullpen cannot be made suitable for public consumption.
Perhaps that's why the film was never made. Maybe the corporate overlords looked around, sighed, and decided ...
Nope. Just not possible.
And scrapped the entire project.
Which is certainly easier than cleaning up the Bullpen.