The Journal reports that there are a slew of Freakonomics-like books on the market. Some of them are actually pretty good, few are selling at all. My guess is that the original has outsold its competitors by about 80 to 1.

Sure, in the long run, a blockbuster can create an entirely new market that lasts for a long time (The Model T, for example, or Star Wars) but building your own blockbuster is generally a lot easier than copying someone else's.