Moore talks a lot of shit, and jut cause he said there would not be a sequel, doesnt mean he (or someone else) wouldnt (and still wont) do it.
As has already been said, just look at things like Highlander and Terminator to see that movie studios hold ultimate power as to whether a film with no sequel potential, gets a sequel. The same can be said of DC Comics, especially as they are owned by Warners!
