My first guess might have been that the "traditional" superheroes are indeed seen as being a bit overdone for the younger generation of webcomickers. But the opportunity to reach other fanbases (gaming, fantasy... genres that have a completely different variety of "heroes," if they choose to acknowledge them) also makes a heap of sense. Of course, the "joke vs story" and "strip vs page" conflicts have probably been around since someone first thought to put those sequential story-pictures on the 'net... and it seems painfully obvious which sides won.
I have to wonder if the recent American Sci-Fi Channel show "Who Wants to be a Superhero?" will kick any enthusiasm for the genre down another couple of notches. At least two of the "contestants" were campy, over-the-top heroes straight out of the 50's. Right down to heroic poses, internal monologues ("Must... not... fail...!") and cheesy catchphrases ("Be a winner, not a wiener.") *Sigh*
But it is nice to know that the genre is hardly dead.
And there will likely always be the superhero's younger cousin, the reluctant hero. Often a lack of costume, sometimes less-than-super powers, anger and fear from those they help (especially the vigilante-types), and likely truckloads of angst due to being forced into the role of hero.
Oh, and ditto on the manga sentiments. I can't imagine how it got so popular, but it seems like the majority of Western comickers have chosen to idealize certain... aspects. *Shudder* Regardless of how many different styles and genres can be found in Asian comics.
In order to clearly see what is in the shadows, you must first enter them.