I read an article about Batman recently saying it's been the top selling comic book for at least the past decade.. Answering as objectively as you can , why do you think Batman sells so well and why have Spider-Man and Wolverine not been able to knock Batman from the # 1 spot ?
While it’s been selling very well since the start of the New 52, I don’t think your first statement is accurate.
But that said, Batman is an extremely popular character, and when he’s done well by good creators, fans are going to turn out for those stories.
Same thing, really, is true of Spider-Man and Wolverine. Wolverine, though, has the disadvantage of being more of a team character than a solo character—he tends to sell best in X-MEN rather than in his solo title.