This is the biggest problem when you have an infinate number of earths; somewhere out there every imaginary 'Imaginary Story' actually happened.
I thought that was the
beauty of the infinite multiple universe paradigm: any story you come up with can be a "real" story. This allows great freedom for the imagination.
True but it made the whole 'Imaginary Story' thing pointless. With alternate futures and realities why even have such a plot device? Better there be a reality where Lex Luthor was Superman and a Gold K exposed Kal-El was Batman than it be called an 'Imaginary Story'.
I think of Imaginary Stories as a genre or story-type rather than a plot device. Unlike dreams or computer simulations, it's not a part of the story narrative itself. It labels the story as a whole as being "not real". In a framed story the inner story is also "not real", but it is embedded in a real story, and in principle can affect the "real' world because it is observed (on a computer screen) or experienced (in a dream) by "real" characters.
An alternate universe story is different in that it is to be considered "real". It just takes place in a "different" (but no less real) world than the usual one. Granted the intent and effect is pretty much the same, in that the device allows stories to be told that would otherwise adversely affect continuity. And to some, "alternate universe" sounds more grown-up than "imaginary story".
But in the long run I think there is a difference. If all worlds are "real", what makes the usual world (the one that used to be thought of as the "real" world) special? Maybe the usual world is just the one readers have become accustomed to. And if so, maybe there's no reason why they couldn't become accustomed to another...