There's a big difference between 'many people I know who use a 5-series DSLR are not tempted by the R6/R6II' and what you said, which was, "
Canon is having a hard job tempting [5DmkIII and 5Dmk4] users to the R6/II/III cameras." The former is your personal experience, and I'm not sure why anyone would question that.
The latter is a broad statement about Canon's sales of the 6-series MILCs. A ballpark estimate based on Canon's unit sales vs. revenue suggests that 6-series MILCs represent on the order of 8-10% of Canon's unit sales. Say I'm overestimating and it was only 5% of the >11 million cameras that Canon has sold since launching the R6.
You literally know about 200 photographers. That means the photographers you know represent <0.04% of R6's Canon probably sold...and <0.002% of all the cameras Canon has sold since launching the R6. But you think that discussions with that relatively minuscule number of people accurately reflects the motivations of people buying 6-series MILCs? LOL. (Oh, and please don't bring up the issue of polling, because the statistical underpinning of polling is that the sample is randomly selected from the total population being considered, and 'friends and acquaintances of
@GMCPhotographics is not a random sample.)
So...you can certainly say that the
people you know who are using 5-series DLSRs aren't tempted by the 6-series MILCs. But claiming Canon is having a hard time tempting 5-series DSLR users to buy 6-series MILCs, you have no idea. It baffles me that people somehow think that the relatively few people they know and talk to have any relevance whatsoever in terms of the camera market. The world is a big place.