Apparently, neither Mark Waid the writer of "Birthright", nor 60 some-odd years of other distinguished comic book writers meet your standards for genius...
For what its worth, "Birthright" is more or less modern canon for the comics.
In "Birthright" Mr. Waid modifies canon and makes the \S/ the symbol of Krypton. Not the House of El family crest.
"That's what I'm getting at. That if the 'S' is just something Jonathan Kent cobbled up out of thin air so he can call his son 'Superman,' not only does it have no resonance, it makes no sense. Why would Clark think he needs something like that on his shirt? He's a humble man. Likewise, if the 'S' is an El family crest, as cool an idea as that was in Superman: The Movie, I will argue until the end of time that Superman's destiny is not to carry on one family's linage near as much as it is to carry on for an entire culture, an entire race. We don't call him the Last Son of the El Family. We call him the Last Son of Krypton."
Mark Waid-Superman Birthright
In the history of Superman, the \S/ always stood for Superman until S:TM came out. In that movie, the writers effectively changed 40 years of canon and made the \S/ the symbol of the House of EL...
Ergo, the one thing we can say is that the \S/ symbol is whatever the writers want it to be whether a stylized 'S', the EL family crest, the Kryptonian symbol for air, or the actual symbol of Krypton.
The one thing to remember is that the Legend of Superman is a living, breathing, enduring,
yet ever changing, myth.
And, it doesn't take a genius to figure that out...
