Just another thought: for sure Canon have listened, and are listening to, the pro photographers, to get the pulse on current and future trends and requirements.
It seems that they have not considered a high megapixel count body to be a priority for the majority of their users. In all fairness, the pro market is dominated by sports and event photography; and for these two areas, Canon have the bases pretty well covered. As for the "enthusiast" and "fine art" photographers, they have a small impact in the pro sales market, and Canon have that covered too (5D and 6D series).
In the last couple of years, they have responded to pro market trends, with focus on the high quality cine cameras. Now that that is done, for sure they will introduce the high res body.