Going on what I've seen on shelves, the shipping numbers are very misleading. The Alliance and Defiance comics are clogging the shelves at Kings Alongside the Allspark comics).

I think that Max Dino's has suffered thanks in part to the nature of Furman's story which while fantastic, was not an easy series for new readers to get into. The treatment of Revelations may not have helped, and there is plenty of negativity over AHM which may have also had something to do with it.

I have said it before, and I'll keep on saying it because it's true, IDW do not market their Transformers comics enough.
Sure there is a dedicated following from fans, but they are very obviously not bringing in new readers, and they wasted the interest in Transformers that the first movie generated by having such terrible movie based comics, and having very few other titles on the shelves around the movie's release.