Yes, of course, because DC Comics is one guy making all the comics. Marvel too.
You know that different writers do different things with comics, right? Frank Miller vs. Grant Morrison, Alan Moore vs. Geoff Johns. How many times has Superman's origin story been revisited? Original Earth-2 Pre-Crisis Superman, Byrne's Post-Crisis Superman, Waid's Birthright Superman, hell Geoff Johns is writing SUPERMAN: SECRET ORIGINS this summer!
Hell look at the entire run of Ultimate Spider-man; Bendis takes key points throughout Stan Lee's Spider-man's history, starting from the origin, and reinterprets them into a tighter, more focused, more cohesive story. I mean come on, the original Clone Saga lasted over three years; Bendis does it better in something like four issues. And you can bet your ass Bendis will never resort to "It's MAGIC!" to nullify 20 years of wedded bliss between Peter and Mary Jane Parker.
As for fan-fiction and fan-art being nothing but kids fantasies, those kids fantasies are the very basis of most modern fandoms. Nothing ever comes of them? Just because they don't get packaged up and sold means they're worthless? Just because it isn't "mainstream?" Bullshit. There is plenty of worthwhile fan art and fan fiction out there.
And doujinshi isn't mainstream? Clearly you've never even heard of Comiket.
And you know what? Where the hell do you get off saying this?
I'm sorry, but you don't know a damn thing about the intentions of any of the remixers here. So quit being so presumptuous.