Well if the reality of the multiverse were legally & scientifally proven (to almost everyone's satisfaction), the "top brass" at DC could deny it all they want. Nobody would care what DC's opinion was. It would be funny though; everyone sees proof positive of infinite parallel universes, divergent timelines, inter-dimensional travel, & even eventually time travel; Then DC starts screaming how there is only one universe. The guys at DC would find themselves lumped in with "flat-earthers", "holocaust-deniers", & other fringe kooks.
As a member of the Flat Earth Society, I object to that remark most strongly.
I can imagine earths where genres other than superheroes dominate american comics. On some earths it could be pirates. On others it could be westerns, or horror, or science fiction, or romance. Infinite possibilities.
I think I mentioned this in another thread, but if there are no superhero comics that achieve popularity, we would see a rise of appreciation and popularity for artists like Don Heck and Gil Kane, who, even when drawing superheroes, make their costumes look like real clothes, and while they can draw good looking women and everyday actions, they have problems with fantasy elements that supercomics emphasize, like robots and superspeed.
Of course, it might be interesting to view the geniuses of comics on our earth, on a counter-earth produce destructive schlock: namely, Steve Englehart's counterpart Stevil Engelhate, and Alan Moore's evil counterpart, Alan Less.
Hey, here's an idea: in an alternate future where the Vikings quit being such sissies and settled in the United States, would comic books be mile-long murals like that one of the Battle of Hastings?