To me the D6 appears to be a D5S - a D5S I have liked to buy some 2 years ago
Well, it is not common that Nikon develops a whole new state-of-the-art AF module every two years (the previous genuinely new module before the D5 in 2016 was from the 2007 D3, tweak a couple times over 13 years, then the D5 gets a genuinely new one and the D6 four years later again gets a new module). Since Nikon's Kenji Oishi says the AF system of the D6 is a "dramatic jump" from the D5, I am willing to give them the benefit of doubt and assume that indeed it is a significant improvement. I'm surprised that people aren't more excited about it, I think pretty much nobody expected a new module and it wasn't mentioned in the rumors.
Photo industry is not only serving needs but beefing up their products with features creating dreams and illusion.
Yes, sure, but in the end the performance and results are what matter, not imaginary things.
In this aspect the impression is inevitable that former pro-level leader nikon is not on par with Canon any more
I thought that Canon took over in early 1990s and has pretty much held onto that position, so this isn't really new! At sports events I always see many more Canons than other brands.
As for what Canon did in the 1DX III what they produced is a new AF system for the viewfinder photography (as did Nikon) but without evaluating its performance, it's difficult to know if either of them is ahead.
Canon also put in a lot of video features into the 1DX III, but I don't know if it is sensible to use this type of a brick for video unless as a second or third camera. There is no viewfinder for video and the camera is heavy. Nikon put video feature upgrades into the Z6, Z7, D780 and D850, less so in the D6. I think the lighter bodies such as Z6 make more sense for video work since there is a viewfinder that can be used, there is no extra mass of optical viewfinder components that cannot be used in video, and so handling should be much easier on rigs that can be lighter weight. I just don't see why video features would be so crucial in a D6 type camera. Apart from video features, what "dreams" did Canon invoke?
To me Canon have a comprehensive DSLR lens system which is their main strength. Canon's fast superteles are lighter than Nikon's. On the other hand Nikon have the 500 PF which arguably wins the lightness contest easily. However, in mirrorless Canon have a scattered approach with separate APS-C and FF mounts and the APS-C system has only a small number of lenses and primes are mainly around normal and moderate wide angle focal lengths. The FF mirrorless system has a lot of exotics (f/1.2 primes and f/2.0 zoom) and only two sub-1000€ lenses. I thought mirrorless was about getting a lighter weight but high quality system; how do RF system users compile a light weight setup? Nikon have 14-30/4 and 24-70/4, both getting excellent reviews and compact. They have a set of 5 new f/1.8 primes all again so far reviewed favourably. To me this is a much more sensible approach to mirrorless. But somehow the market likes Canon. It's as if they only sell a dream, not what is really needed, and the customers take it and swallow greedily. (Canon did produce a set of f/2.8 zooms and that's probably what many users will buy. But we can't really talk about a compact setup in such a case. The 70-200/2.8 is compact for its specification but loses some focal length upon close focus so it's kind of what you see is what you get.)
I like the Canon R5 button and control layout from the back of the camera, it seems they put in all the controls that are needed (wheras the main control wheel is missing from the R). However, it is difficult for me to believe it would be affordable. Yes, dreams, but does the reality match up?
For example, what I would like to do with mirrorless is photograph people quietly with a smaller, less obtrusive camera setup and quieter shutter. Right now the electronic shutter comes with some drawbacks but the mechanical shutter of a mirrorless camera still feels quieter than the combination of mechanical shutter and mirror movement. The Z7's sound is quite pleasant in my opinion. So with it I could photograph people with less attention being directed to me than when using a DSLR (though the D810, for example, and many DX models such as D7200 are quite quiet also, and the quiet continuous mode can be useful).
In these situations where I want to photograph people at close distance, aside from quiet operation, I need a lens aperture that is large enough that I can get high-quality images. I would say f/1.4 and f/1.8 both qualify when used with modern FX sensors. An f/1.2 is unnecessarily large and I consider it more a special-effect lens. For this type of photography, I might want to use 20/1.8, 35/1.8, 50/1.8 and 85/1.8. Nikon already offers such a set costing about 3500€ (less if timed for rebates). If I wanted to get four primes from Canon, I could not build an equivalent set and if I wanted native primes, I'd be spending many times more for f/1.2 lenses that are not best suited for photographing without drawing attention to me.