I think for the modern chapter you have to blame For All Seasons at the very latest.
Byrne's starting points were the early versions of the origin where Pa inspired Clark to become Superman from his deathbed and then how Superboy changed all that. Keep in mind of course that Byrne's earliest take had a different approach to the beginning of his superhero career, but his point was that the deathbed inspiration and killing of the characters were arbitrary, as Superman doesn't need a lesson in becoming a good guy.
http://www.fortressofbaileytude.com/...rne-interview/
By the time Superboy was introduced, Siegel already had a different approach to Superman though. The chapter with yellow lining on the boots was already more humorous and "superhero" than the street level stuff for which the creators are usually cited. If they tried the earliest take on Superman around when O'Neil came on (and you can argue that that's really what he tried anyway) you could probably get people who were used to the 60s Siegel to cry about the rough edges.
The unpacked, earliest take from the strips extended the introductions of Jor-L and Krypton. There was virtually nothing on his uprbinging though, where apparently he just stayed an orphan. You could assume that it was quiet enough though given he's perfectly established to be living as Clark before Superman or his introduction to the Daily Star shortly after. The 40s intro of Superboy is a big part of this whole thing, but I'd also point out that it really wasn't a continuity that early on either. The Superboy feature really didn't define the Superman features, and even looking at it separately from what (little) I've seen it took a bit before Smallville was a wacky setting as opposed to being a normal home to a wacky Super boy.
When it comes to his mission, going back to your earlier post, there isn't really a connection between his upbringing amd decision to fight for the little guy. That fits no matter which origin you give him, provided you're not subject to playing in the big DC sandbox.
The Rockwell thing seems like a broad and slightly pejorative term. It does fit as a description in a sense but the emphasis is kind of defeated with things like the Manhunters of Millennium or the flat out alien cast of Hamilton as others have taken into account.