Exactly. And you would have taken the exact same decision 2 years ago if you had owned a 6DII instead of a 6D, right?
The comparison btwn Canon and Nikon is not very relevant, because the switch is costly however superior the Nikon may be, and new entrants in the SLR world are likely to go mirrorless.
So the only hope for Canon is pretty much to convince 6D users to buy 6DIIs, right? Who else would do such a thing? Canon APS-C users wouldn't be able to use their lenses on a 6DII, they will go Sony or Nikon if they prefer cameras with OVFs... and take a fact based decision.
But Canon also has lots of marketing cash... and many buyers will based their decision on biased information... I just feel sorry for them. I would think that you and I agree that leading them towards better solutions such as the Sony offering will help them, right?
Cheers,
Bernard
The thing is, each person will have his definition of "better solution", as it is a personal decision. Again, from the DPR review conclusion:
"What the 6D Mark II is, though, is a solid, well-built camera that is capable of producing great images while improving upon its predecessor in almost every measurable way."
So the 6DMKII actually and factually improves upon the 6D in almost every way. For example, the movable screen may be reason enough for some to upgrade.
In my case, I waited two years to see where the Sony FE system was heading; once the cameras matured, and more lenses were available, I changed. I do agree that for first users, there are today many other options in the 6DII tier; many more than 5 years ago, when the original 6D showed up.