So is it true that science fiction book sales have dropped since the economy went dystopian? Not according to one publishing industry insider, who has access to actual Bookscan data. Apparently, the data show a slight increase in science-fiction book sales for 2008 over the year before, and no evidence of a steep plunge so far in 2009.
As always, the fantasy book market is stronger than the SF market, and fantasy has a healthier midlist. And the overall trend in SF book sales, over the past several years, remains one of decline - but there's no evidence the economic shitstorm has hurt SF. (In fact, somewhat the reverse, perhaps because people need more escapism and looks into a more distant future.)