I understand your reasoning for how you expect the EOS R to perform but at the end of the day you are still making assumptions about what you think is likely to be the case. I would rather have more information about what actually is the case before I made such a "big decision". It may turn out exactly as you anticipate - or it may turn out there are surprises. I would want to see independent reviews - and user comments (as against reviews) - which describe how things perform in real use before I decided to buy. I mean, to give a simple example, you say no should expect battery life to be as good as for a DSLR. Fine, but what is the difference in real use? Actually quantifying the difference may sway some people one way or the other. Another example is the Digital Photo Preview talking about the touch screen being laggy. If I thought I was seriously a potential buyer for the R (unlikely at this point), I would want to hear more about exactly how it performs in use under different conditions.
And no, it's not a case of "either you want a Canon mirrorless or not". I'm sure some people think that way, but for me - and I think many others - I do not fundamentally care whether the camera has a mirror or not. I am just interested in what the camera is like (its pros and cons) to take photos (or video for those interested in that).
As for buying and returning it, I assume you are in the US. Not everyone has such relaxed and generous returns policies. If I bought the camera and simply didn't like it, I'd have to sell it on the second-hand market. If I was somewhere where I could easily buy and return, I expect I'd be much more likely to say why wait for someone else's review when I could buy it and try it for myself risk free.
Anyway, there are always going to be people who are keen early adopters, and that's fine. If you are happy to spend your money that way, great (or maybe you have the option of buy and return so there is no real risk for you). What I don't understand though is thinking it laughable that some people aren't keen to put their money on the line when there is only very limited information available.