Zigzagzoe, you obviously have an affinity for the D8xx (and/or possibly just anything with Nikon's name on it, or anything with a Sony made sensor) and you created a fresh account on a Canon site so you could inform everyone of your preference - and that is fine. The D8xx is also a fine camera, for some photographers, because it can provide a specific solution to a specific need - not because it, and Sony, produce the end all be all in photographic reproduction.
(Sorry.. I don't really do quotes, and even if I did there are far too many needed to address the volume of brand-fan-biased statements made in your posts - and I am long winded enough as it is.)
The A7S has a great sensor in it, and is a pinnacle example of what a large percentage of the industry (not just Canon users suffering from mp-envy) have been proclaiming and wanting for years. Which is to put todays tech in a sensor that provides minimal work flow in a package that offers lens flexibility, SLR AF performance, reasonably flat ISO performance curve, and solid field ergonomics. The A7 line obviously does not come through in all those areas, most notably lacking in system lens selection and ergonomics, but does demonstrate that MP and +.5ev shadow DR at base ISO is not all there is to this industry. I think the resistance you encounter might stem from your perspective that the area of photography that takes place at base ISO is so significant as to be all that counts in photography when coupled with less than half a stop of shadow DR... and obviously (whether mentioned or not) a complete acceptance of data provided by a rating-for-hire service like DxO - and that is fine as well, for you.
The reality however is that across the entire spectrum of photography more images are captured outside base ISO than within - and at an exponential level - and that is where the D8xx is simply bested by many, if not most. Therefore evaluating the performance of a camera across a reasonable sensitivity range is more relevant and substantive than what might be produced at one specific sensitivity setting. That is not to say that low ISO isn't relevant, but attempting to quantify in comparison to something like the popularity of low speed film is quite skewed. ASA64 speed film for example was certainly popular, and because it did produce the best imagery, however that was/is because of the limitations of light sensitive substrate materials - not because lower sensitivity always produces better IQ. Digital imaging technology does not actually have a 'native' operating range, it is not limited by any specific sensitivity, it is simply the design of the sensor chosen by the manufacturer. Standard film sensitivities are most often targeted in digital sensor design because our environment (the intensity of sun light) and photographic preferences (controlled dof) etc, maintain a demand to retain those sensitivity settings. As an example of preference versus need; Once ASA200 and ASA400 were being produced within acceptable output standards (mid1970s) those speeds not only sold more than lower speed films, even during the rather limited time of sale (~1970 to early 2000s) they accounted for more sales than the total of ASA64/ASA100 film combined. Even if we concede that base ISO were ones only requirement, you still could not evaluate 'pure' IQ -purely- on DR (the only component of IQ something like the D8xx has over anything else) as literally everything else in the visual spectrum are factors of the whole. Measuring 'pure' IQ purely on DR is flawed logic and indicates one who does not know enough about what goes into IQ as they should.
To continue visiting something like the D8xx; The majority of its DR 'advantage' only exists in shadow/dark regions, AND only at base ISO, AND only by .5ev, which is a very subjective need/benefit. If a photographer has no need or intention to raise the shadows of an image then the D8xx offers nothing other than MP, which is an even more subjective need/benefit. DR range (as is measured and rated today) is not an measurement of accuracy, it is a range of a spectrum. If you plotted visible dynamic range on a linear scale (-6 to +6 in this example) the D8xx at its best sensitivity setting offers nothing that is not available from any other camera between say -4 to +4, and when certain exposure modes are enabled it can be increased to -6 to +5 staying within its best sensitivity setting, which is great. However maintaining honesty its curve in highlights steepens to the point of clipping prior to its increased highlight range. Basically it offers the user an option of trading some detail in its increased highlight range to gain some shadow range, which brings us back to the previously mentioned 'advantage' - if not raising shadows, it is purely subjective benefits.
In comparison, the A7S provides an exceptional performance range that would benefit a greater percentage of its industry than anything else available. At base ISO it provides greater IQ (DR + TR + CS) than anything on the market, and through its operating range it maintains a performance curve advantage that just gets greater as ISO sensitivity increases. As is proclaimed by DxO, it is -currently- the king of low light, tone, color, and even DR (because the majority of photography doesn't need .5ev of recoverable shadows at ISO100) - BUT just as IQ is a measure of more than one parameter, a camera is measured by more than its sensor. Were it not for a very significant failing in system lens options and ergonomics the A7S could very well displace a substantial amount of Canon/Nikon market share.. as it is though, as a whole, it simply fills a void, of a niche, just like the D8xx and every other camera that has ever been produced.