Unlike Superman, our definition of who Captain Marvel is, and what his stories are about, is perpetually trapped in amber in the 1940s-1950s.
It could be argued, even though Superman
has received continuous publication, that he too is trapped in a certain amber...that of the radio show, the Silver Age comics, and Superman: The Movie.
[...]
Superman has been unable to escape the limitations placed by these three sources (not that it's a bad thing.) Just ask "electric blue" Superman. DC even tried to escape these limitations by confining Superman within Byrne's new limitations of the mid-80s, and that didn't work either....everything that Byrne did has now been explained away as an anomaly caused by Superboy Prime hitting a wall. The best-selling Superman comic today, All-Star Superman, features the continuing adventures of the Silver Age Superman, and Silver-Age style writers have been hired for the regular titles.
[I originally wrote a long post whose basic theme was "Byrne: bad guy or villain?" But I have elided most of that in favor of something a bit more connected to the post I am following.]
I wonder if the persistance and re-emergence of that Superman isn't because it hit such a chord with so many readers that just nothing else has really improved upon it? Different is sometimes worse. In the sort of evolutionary contour map that exists for comic characters, maybe nothing that Byrne did was really an improvement on what had gone before.
A similar dynamic may be at work with CM. I was never a big fan and don't know too much about him that couldn't be learned from the
Superman Vs. Shazam tabloid comic. But, he was a successful character for quite a while and I wonder if it wasn't in part because he occupied sort of the Superman niche of his world. In their shared post-
Crisis world, there was an effort to further distinguish him from Superman, but, as successful as the Silver Age Superman is, the a-little-different-from-Superman territory is tough ground to hold. I would argue that Byrne and his successors found out that even a character with a big S on his chest doesn't hold it very well without whatever magic they jettisoned from the previous version. Add to that the fact that the Superman fans already have a character and finding a successful niche for Cap gets even tougher.
Anyway, I think that's part of the dilemma with regard to this thread: whatever lessons the CM team might learn from the S-books, they have to put them to use in a way that doesn't make Captain Marvel into a Superman clone. There is arguably only room for one Superman in continuity (as previous incarnations of Supergirl books, for instance, have discovered) and even he really only seems to achieve peak success when characterized in a certain way.