Update:In the comments, FlavaBlave — by way of his wife -- offers some further thoughts on what makes this photograph so much more expensive than other photographs:
I’m an economist so I was confused about this as well. My much wiser wife had to explain it to me:
“1) This is a realism imitating contemporary art, which was a novel concept in the early 80s. A reversal of artistic influences that had never been explored.
2) Technically it is spectacular and I’m not sure how someone could shoot a picture like this before photoshop. There are tons of technical feats, but the first one I noticed is that the horizon, both edges of the river and the sidewalk (all lines in the picture) are totally straight and run parallel. Not just one or two lines but 5 lines! In nature 5 perfect parallel lines are virtually improbable to find. So, another aspect of the picture is that nature is impersonating modern landscape, not just modern art.
3) Land naturally has a curve as well, so he must have used some correcting lens…I would imagine, but lens would probably have to be custom made for the landscape.
4) The balance of colors is also a technical accomplishment. Because the river and the sky are air and water in completely different fields of perspective yet they look the same and have the same color. The same goes for the land in the foreground and the background, notice, it matches. How do you make land half a mile or more away look exactly the same color as land only 20 feet away? Colors get dull the farther away they are from the camera, but he was able to fix that problem….somehow…not sure how you would do this. Maybe another custom lens could be used?”