I think it's not even that they don't push the titles, but that it's almost like they TRY to make them not sell.
The most simple and obvious case is COD: Ghosts. It's not like it needed a major push and was never going to be a huge seller, but Activision denied its existence for months, even though it was obviously in development for more than a few days. The Wii U logo was absent from marketing. It costs no more to include a little blue U in your ad spots than to not include it, so why don't they?
The only explanation I can come to is funding from MS and/or Sony; I've heard that Activision gets a cut of Live revenues, though I don't know if that's true. But the issue isn't so much about lack of push, but that 3rd parties are actually pulling on the success of their titles. The Mass Effect debacle is even more extreme, and there are others. But the subtle things like Ghosts make no sense.
