I can think of another reason (and I am sure, that there is more that one reason for that dreaming of a price-tag):The $1000 or whatever price is not really part of the dream. They dream about a camera they know doesn't exist and won't be build by any company.
The price is meaningless in this case, but in our society everything has a price, and if you put a price-tag on your dream, it's one step closer to reality, regardless how ridiculous the price is.
If you don't put a price-tag on, it is guaranteed, that two minutes later someone posts: yeah, but that camera of yours would cost a million of R&D, and you would never be able to pay it anyway, so dump your stupid dream! - And then you have to deal with that instead of sharing your dream with the people.
I know, I dream of cameras. But when I do, I don't put a price-tag on, but I also don't share the dream, yet. Instead I dream of the camera I would build, if I could. This skips that whole part of the discussion. 😎