There's a good discussion here on Groovy Age of Horror, referencing some of the same territory I'm talking about with my Fryean concept of modes: the notion that every genre depends on a set of "logical conclusions," even if those conclusions spring from an illogical set of premises, as is often the case with the superhero genre. Genres and modes are obviously not the same thing, but for the purpose of this argument I'll pass over the differences.
Curt mentions that when Rick Veitch outlined his ambitions for BRAT PACK he spoke of "destroying the superhero." Frank Miller and Alan Moore have made similar allusions to undermining the genre with DARK KNIGHT RETURNS and WATCHMEN respectively, and more recently Zack Snyder, following in their deconstructive footsteps, claimed that his WATCHMEN adaptation would be the last word on superhero films.
Such declarations suggest that the speaker is extremely naive, though I've also considered the possibility that they're made with an eye to garnering media-attention. Certainly being the person who has the "last word" is an enormous boost to the ego, rather like the belief of the apocalyptic Christian who rejoices that even if his generation can't have the privilege of being the first, at least they can be the last.
Certainly this sort of hubris was not born with the "grim and gritty" era of comics in the 1980s (which really got started in the 1970s, but that's another story). The earliest practitioner of genre-hubris was probably the fellow whom Alan Moore feted as his favorite comics-creator: Harvey Kurtzman, best known for his satires of superheroes and other pop-entertainments in MAD MAGAZINE.
There's a Kurtzman quote in his longest COMICS JOURNAL interview that I haven't time to look up just now, to the effect that he felt that he had accomplished some great breakthrough when he took the dominant image of the superhero (courageous and supremely competent) and inverted it, so that the superhero (as seen in the classic 1953 "Superduperman") was a loser and a goof.
In the larger historical sense this was, of course, no more a breakthrough when Kurtzman did it than when similar heroic skewerings were undertaken by Cervantes and Voltaire. Both satire and its close cousin comedy depend on the inversion of desired expectations, but this inversion is simply another expectation, not a liberation from expectation, be it that of genre or dominant ideology or whatever.
Kurtzman's MAD satires were, of course, supremely funny, but they didn't disclose any reality but the narrative reality of the satiric mode. And though Kurtzman might have desired to see his "Superduperman" expose the implied banality of its model, his satire probably had no measurable effect on the prosperity of SUPERMAN. Indeed, within three or four years of the satire, the feature became far more inventive, possibly in response to the growing appeal of science-fiction in various media of that decade.
Kurtzman's satires, though, might be deemed as more straightforward than those of Veitch and Moore (Miller is an exception in that he was doing a romance-adventure with satiric elements). Because Veitch and Moore did essay ironic superhero stories with adventure-elements, both had some influence (however good or bad in the long run) on the development of mainstream superheroes. All artists are magpies: they swipe from the creative "nests" of other artists anything that they think will work for them and/or their audience, and any artist who denies this is either a fool or a liar.
Kurtzman would probably have been pleased that the mainstream heroic comics of his time did not derive much (if anything) from his satires (the various spoofy imitations of MAD being outside the frame of that mode/genre). Thus he could go to his grave believing that he had "subverted the dominant" or some such ideological fantasy, and without giving any aid and comfort to the enemy.
Others, however, could not say the same-- the least being any so-called "destroyers of superheroes."