My book cost $6 to print for a 5,000 copy run, $5 to mail and perhaps twice that to sell. Development and research costs exceeded $30,000. Then there was the patent at another $8,000. I took three years off work and blew $250,000 in lost income to write it working an average of 60-90 hours, six days a week (probably understating that). That's a total of over three hundred grand.
What they are getting is a transformational book that may be of historic import (and it's pretty too :). If people think that the home-delivered cost of $35 is too expensive for my 450 page paperback with 350 sources they can go stew in ignorance wishing things were different. It's cheaper than a couple of tanks of gas.
Did you see Jeff Heads reply. I think you both nailed that one to the wall pretty good. I thought your book was worth it as you surely know by now.