My impression is, that Nikon has been affected by Sony's FF mirror less cameras much more than Canon... Those that don't care on having an OVF, or those that video is important to them, would prefer a Sony mirror less than a mirror box Nikon... Some still life pros that work tethered in studio and perhaps use their FF camera as a back on a shift/tilt device (like an old view camera) would clearly prefer a mirrorless Sony than Nikon... Also... very few videographers use Nikon... Nikon has to work on that... it's a huge market segment.
You talk to anyone that sells cameras on the medium to high end for motion and they all scratch their head why Nikon doesn't/didn't make a killer combo stills or motion camera.
Obviously Nikon is smart, sees the advantage in motion imagery, (hence the big advertising push for motion and their "video kit" for the d810).
They could have made a super 70d, with an apsc (super 35mm) 4k crop in camera for motion and full frame 35mpx stills all in the same body, with decent preamps, touch screen the while 9.
Most people assume it has something to do with their contract arrangements, maybe with Sony, or maybe they just fell asleep at the wheel and didn't think they needed it.
All the Japanese companies do some silly things, or protect market share.
I just bought a 70d for a production that needed touch screen focus and a decent 2k file and the 70d is pretty amazing in that regard and produces a somewhat hefty file, with an all intra 1 minute clip is about 400mb so it grades well, focus tracks well, is sturdy and aps c is the perfect size for motion, which somewhat parallels, super 35mm in crop and mindset, but then there is the things Canon leaves off.
Like a headphone jack (which isn't a deal breaker with an external recorder), but if you use the hdmi out, the touch screen lcd on camera blanks out (which is really unforgivable). Also 2.5 K capture and then downsampling to 2k (like the Arri) is about the minimum to cut alaising and moire which the 70d sensor could do, though probably would need some heavy horsepower to process.
If the 70d had the features mentioned, or even 4k they could ask double, triple the price and nobody in the motion world would blink, but I guess Canon, like Sony thinks about protecting market share on their higher end cameras.
In other words, I feel it's either marketing, or some kind of agreements that hobbles innovation as much if not more than available science.
IMO
BC