I'd just like to point that I was right now shopping amazon.com for some books that I'll need for my academic research, and I found that a 506-page hardcover text-only book sells for $200 (fortunately, there's $50 paperback version). Other books I also need are selling for about $120-$130 each in their hardcover versions.
I got two conclusions from that: first, they should try selling paperback versions of the core rulebooks. Second, $50 for a full-color hardcover of 300 pages seems to be dirty cheap if you're selling for a niche market.
Now I see why some accomplished RPG designers create games on their free time instead of doing it as a job, and not even WotC manages to make enough money to call this a chief business.