I asked the same question myself. Here's the math: designing a 250 pages book by a professional designer, having it edited and checked and printed by a professional printing company (which is NOT the same as having a PDF printed), will costs me roughly € 15.000.
Then there's the photography that is needed to add quality to the book. Otherwise, it would be more or less a bunch of scans of old magazines and brochures. The great people who do the photography are working very, very low cost, because they too want to create this fine book.
Included in the € 30.000 budget, are the shippings costs for the books (between € 6.000 and € 7.000), the 5% fee that the Kickstarter platform charges and the 3-5% fee for the guys from Master Card and Visa.
What is left for me? The covering of my costs (gasoline, train tickets, a few hostel overnights, coffee) and a life changing experience :-)