This applies to both DC and Marvel, though with Marvel more aggresively pushing synergy between the various medias anyway, I guess its a little more pertinent to DC.
My question is basically - to what extent does the 'mainstream' 'in-continuity' version of a character, published in the 'mainline' book in the 'mainline' universe, really matter anymore?
I mean, obviously, they matter to the die-hard fans. And perhaps even to more casual ones. They keep these characters alive in the medium in which they were created, and continue to provide material for new adaptations.
But if you really think about the place that these characters hold in the collective pop-cultural conscioussness of the world, if you think about the most popular interpretations of these characters, and the versions of these characters subjected to the most discussion and debate - then it usually isn't the version of the character who shows up in the 'mainstream' books month after month.
I mean, what really has more relevance when it comes to shaping most people's perception of Superman? Brian Michael Bendis' current work on the title, or the Donner Superman movies and the DCEU? Or Smallville or Lois & Clark for that matter?
Consider Batman. Is Scott Snyder or Tom King's work really as influential to the character as Batman: TAS, the Nolanverse, the Adam West show or 'The Dark Knight Returns'? Or even the Arkham games for that matter.
Even if you look purely at the comics alone, you'll find that very often, the most iconic stories featuring a character may be years, if not decades old, and potentially no longer 'in continuity'. That applies even to the more recent stuff.
With Superman, you've got 'All Star Superman' and 'Kingdom Come'. With Batman you've got 'The Dark Knight Returns' and 'Year One'. More recent stories that have created a buzz for these characters include the Earth One OGN's, 'Batman White Knight', 'Superman Year One' etc.
It goes beyond the Big Two of course. Even after they were comprehensively rebooted, the popular vision of the Titans remained the 'New Teen Titans' run by Marv Wolfman - the run that inspired the cartoon and now, more recently, the TV show.
The fact that Scott Snyder's Justice League lineup so closely mirrors that of the DCAU cartoon, and that so many people regard John Stewart as THE Green Lantern, is also really telling.
One-shot stories set 'outside continuity' have always been popular and often create more buzz than anything mainstream. Earlier we had Elseworlds, then the Earth One OGN's. Now we have Black Label.
It really makes you wonder though - for all the quibbling we do over continuity and the current runs, a lot of that stuff ultimately doesn't matter much to the overall perception of the character and their brands, if at all...