They could advertise the product fairly inexpensively, it's FOX, they have resources already in place that would cost little to nothing to utilize for this purpose. They choose not to, that's their choice to make or not make. They could also go whole hog and splash the airwaves, social media, television, and the internet with millions in advertising. At the end of the day, whichever route they choose, they'll still have the same basic problem they have right now. Customer retention.
I don't know what the answer to the problem is going to be, but I would think it almost has to involve WIS stepping up their game in the area of communication. It seems to me that they keep trying to correct the problem by sweeping overhauls of the product. I don't work for FOX or WIS, so I don't know if that's their intent or not. Or for that matter, if they even view the lack of retention as a problem.
I do know that the transition to HD 3.0 has been, thus far, the SMOOTHEST change WIS has ever done in the time that I've been playing HD. You may or may not like the new HD, but it's hard to deny that there have been relatively few effects from this switch that are percieved as "Disasters". by the oversall user base compared to every other transition HD has been through. I'm not suggesting that it's a better game now, nor am I suggesting that it's worse. I'm still getting a feel for it and I will be for a few more seasons yet. They still have some issues to correct, some new, some old, but I'm giving them credit for this transition being very smooth and relatively pain-free. That in itself is a MAJOR step for WIS.