Canon's sensors do not "lack" DR: some older Canon sensors are prone to more pattern noise in pushed low ISO shadows (which is not the same as less DR), but the latest Canon crop sensors are essentially FPN free (completely so, if you use DPP), allowing for multiple-stop shadow adjustments without detriment; and they also have more than enough headroom at the top end of the histogram to allow for a more ETTR approach.
And beyond about 800 ISO - no DR difference anyway.
You stressing the lack of DR difference above 800 ISO means you at least acknowledge the difference of DR at lower ISO?
If there is a difference at lower ISO but no lack on Canon side, does it mean that other cameras have more than enough DR?
That is at least one statment most here will clearly disagree with, Canon user or not. There are many scenes of photographic interest where light is such that even 2 more stops on top of the class leading D810 would still bring more value. Yes, there are scenes where a point & shoot will have plenty of DR but I'd rather not have my equipment dictate what I can photograph comfortably. Although I liked the look of slides, I loved knowing that I could use negatives when needed.
If you recall, many MFDB users have been spending tens of thousands of US$ for years mostly to get better DR, yet the latest Sony sensors are ahead of these MF wonders and the gap with Canon FF is significantly larger than the gap ever was between 35mm and the backs.
The way I look at it, Canon's inability to compete credibly on this metric, and the denial of some Canon users, is hurting all photographers by slowing down progress. That's a bit annoying.
Had Canon not released a 3.8kg 400mm f2.8, my Nikon would still weight 5kg. I don't think any Nikon user ever claimed that the obvious superiority of the Canon wasn't real, even if it was possible to take amazing images with the excellent Nikon 400mm f2.8 VR.
Cheers,
Bernard