No I'm not disputing it...but you are implying Canon's market share is based on the low end consumer cameras whereas Nikon sells only high end cameras. Where are your figures for this?
Both companies have seen an important decrease of absolute sales numbers and Nikon obviously also sells a lot more low end bodies, but I believe that the decrease of Nikon in the value segment among knowledgeable photographers has been a lot slower than Canon.
Two main sources:
1. A wide set of empirical inputs coming from people around me, the perception I get in forums,... just to give one example... you and I. You abandonned Canon in favour of Sony, I still happily shoot Nikon,
2. A pretty regular tracking of sales ranking demonstring pretty clearly that the top ranked Canon offerings overall tend to be APS-C discounted kits while Nikon tends to be better specced bodies
So unless you have evidence of the contrary, this seems to be fairly reasonable data to base an opinion on.
It appears that the Nikon Z is selling a lot better than the Canon R for now. Which isn’t surprising when you compare the equipment that has been proposed by both brands if you try to be objective.
Cheers,
Bernard