For Batman to have no referents whatsoever (which is what Nolan seems to want), one has to imagine a US with no history of masked vigilantism at all, no Ku Klux Klan or anything like that, which would be used as points of comparison in the absence of fictional masked heroes.

But I think there’s something to it. It may be the only way to do “protagonist chooses to be a superhero” and still produce an effective story. The conventional superhero film (Spider-Man, Iron Man) turns on the decision to use the hero’s abilities in socially beneficial ways, and takes it for granted that the way to do that is to become a superhero.

But if you want to make the film about the decision to be a superhero as such, then you would otherwise need to confront the basic silliness that modelling oneself on fictional superheroes would entail in our world. Hiro in Heroes can only be played for laughs.

So here goes: the Batman you talk about, where Batman is the real person and Bruce Wayne the mask, has become the dominant way in which the character is seen by the broad popular audience: it’s implicitly the view of Burton’s Batman films and explicitly the view of the Nolan ones.* (The Schumacher films, of course, were not troubled by niceties like identity.) It’s a pregnant theme which appears to touch a contemporary cultural nerve.

That might make it difficult to revert to the older model of a well-adjusted Bruce Wayne who poses as Batman (even if that would be richer within the comics themselves – because there dressing up as a bat and beating criminals up is completely normal behavior*).

Similarly, part of why Superman Returns didn’t work was that an audience whose perception of Lex Luthor was formed by Lois and Clark and Smallville wasn’t receptive to the 70’s comedy scientist-criminal.

*Nolan recently commented somewhere that it was important for his take on Batman that there were no other superheroes in this world, not even in fiction.