Well, I disagree. Just like Marvel, Dc is not linear; there are alot of differnt variations of the Dc univers. If so, then why isn't Batman always dating Wonderwoman, or Catwoman, or why does the time, and style of Gothem city remain the same. Why isn't Superman always married to Lois Lane, why in some, he's been morning her...these things are subject to the writers of: the DarkKnight, Batman, Batman Detective Comics, and the other comics which Batman shows up in. Its not One Great Telling, what comics are connected are stated as such. The others are snap shots of that world, at that time, as the writers of Dc, and Batman, of what ever issue, saw fit to tell or change as We, the people, wished to see.
I mean, look at Luthor...he's relation ship, personality, stlye, and reasons for doing what he does, have changed so many times.
But, this just be me, but that's what I, and those who I know that read comics, feel.
Game On.