I could be wrong, but I don't recall any official sources cited. As I'm sure you know, Canon and Nikon seldom definitively declare anything dead.
Good arguments can be made both for and against a high-end APS-C mirrorless body. What no one has access to is the market research that shows if it will be profitable or not.
I'm skeptical, but over the years I've learned not to bet against Craig's rumors, even when they are CR2.
I do agree though that many people seem to be asking for a unicorn, in that they want or even expect that an R7 will be bargain priced like the 7DII.
My guess is that an R7, if it appears, will not be cheap. It might not be as expensive as the R5, but I would not be surprised if Canon launches it at a price that is closer to the R5 than the R6. My reasoning reflects your observation that the market has contracted over the last several years, coupled with the knowledge that the target audience is not particularly price-sensitive -- after all, a $3,000 R7 and a $2,500 100-500 f7 lens are still less expensive than a 500mm f4 EF lens.
I agree there will be lots of complaining if one actually does come out -- either from those who are expecting a bargain or from those who are expecting a high-end body. My guess though, is that it will be the bargain hunters who are disappointed.