Sometimes I think it is a bit of a artificial (non-market driven) price inflation sort of thing.

I just checked the price for Modern Carbon Printing by Luis Nadeau at Amazon, and it was $222 (or $1750 from Germany). When I wanted a copy a year or so ago and saw the price (it was ~$400) I emailed the author and he sent me a copy for $16 or so, which was the usual price.