I think more than anything its that Cannon has really missed the boat when it comes to the transition from still images to video. A decade or two ago, the vast majority of consumers only wanted a camera to shot photographs with, but now most consumers are also at least partially interested in shooting video, with many being primarily interested in video. Other companies have adapted to these changing consumer preferences (Panasonic and Sony especially) while Cannon has lagged behind in terms of rolling out more video focused features like 4K, IBIS, 10 bit color etc. in all but their top of the line models.
My guess is that Canon is afraid of cannibalizing sales of their cinema cameras, like the C300.
Panasonic and Sony don't seem as worried about cannibalizing theirs, which might be a better strategy in the long run. Fuji and Nikon don't sell cinema cameras, so they have no incentive not to move fast on adding video features to their (previously) still cameras.
