Well, I don't think it's quite rational to assume that the sales level of a current book would maintain if you created a second title in a different series of book. It would be great in the abstract if you could say, "Well, we can maintain a book here at this level while launching another one." But I don't think that's realistic in any way.
Oh, wait, sorry, my mistake...that was an answer to why they didn't keep the Hellblazer title going while launching the nu52 Constantine title.
Because 14 Bat titles a month? No problem. But the idea of 2 Constantine books? "Irrational" and "not realistic."
I should point out that Cunningham and DC Senior VP Of Sales Bob Wayne do a masterful job of dismissing every question asked by Newsarama's Vaneta Rogers as the product of a deranged mind who knows nothing about comic books. Amongst their responses (For what it's worth, none of the questions was anything other than what many of us have been asking based on recent DC actions):
Cunningham: No, I think that sort of analysis is extremely surface and doesn't deal with the facts at all.
Nrama: What facts? What facts am I missing?
Cunningham: I don't know. I didn't hear enough of your thesis to know how that works.
Cunningham: That's a bizarrely speculative question. I don't really understand it.
Cunningham: I don't know. What a heck of a question. I guess I'm going to respond to that by saying that framework is weird.
Wayne: I find this whole question kind of odd.
Cunningham: You use that phrase "seems to indicate," and that seems to me to be the problem here...So some of these questions sort of veer into this weird speculation that I don't understand where the basis in reality even comes from.
Yes, that's all from the same interview. No, those are not all of the examples.
Obviously, DC sends these two out on PR runs because they've mastered the sophisticated task of "pretend not to understand every question and then turn them back on the interviewer and imply that she's stupid for having asked it." Well played, sirs, well played.