I didn't reference the short one-page origin from ACTION COMICS #1 in my analysis of the two-part story that introduced the Man of Steel to comics-audiences, largely because it wasn't part of the story proper. Now, as I explore the subject of "how short can a myth be," I have to ask whether the single-page origin by itself constitutes a myth. And my answer is that it could do so-- but it doesn't.
The main Superman story in ACTION was not even the complete story that Siegel and Shuster had assembled in their pitch to the comic-strip syndicates. Even the full story, later fully printed in SUPERMAN #1, doesn't explain anything about the character's provenance or powers. It seems likely that the editors of ACTION #1 felt the need of at least a quickie explanation, and thus readers were given a one-page summary of "who he is and how he came to be" on the inside front cover.
But despite establishing some major myth-motifs. the one-pager never brings them together into a cohesive myth-scenario, so that it is at best a "near myth." In contrast, the two-page origin from 1939 expands on the fragments of 1938, and does assemble a genuine, albeit short, myth-continuity.
The first page is largely "the beginning:"
While the last page provides both the "middle"-- the general sense of Clark Kent growing to manhood, the death of his parents-- and the "end," in which Kent decides to become a costumed hero.
By the time the two-page origin appeared in the SUPERMAN #1 (dated Summer 1939), the comic strip, launched in January 1939, had fleshed out much of the backstory, conveying the first visual depictions of the hero's real father and mother. I may explore the comic-strip origin in more detail at some time, but for now, suffice to say that Superman does have at least one very short mythcomic in his repertoire.