It doesn't make sense at all. AMD will sell plenty of these cards whatever the price is, and so would NV. What recent history has shown us is that enthusiasts will pay top dollar for anything, look what people paid for the Titan.
All the people who want/wanted a £500 card did not all buy a 780.
You're saying it doesn't make sense and then waffling about stuff which has nothing to do with the explanation as to why it makes sense that I provided.
The point is that AMD can't sell as many cards as NVIDIA at a top end price point. Rightly or wrongly this is currently the case. I don't think anybody has ever made the point that AMD won't sell any cards at all or a teeny amount. Of course they'll still sell but it isn't a black/white argument on whether they will sell or not it's about profit.