You've got all these smaller groups in the field that are no longer able to really talk to each other, so there's less of a central conversation... You can't just stick a rocketship on the cover of a book and expect it to sell. That'll work for the Hard SF readership, but that's not going to sell thousands of copies. In the 1960s there were only 150 or so books published each year, so it was really possible for a dedicated fan to read 50 to 100 of them. Now, Locus lists something like 2,500 books published in the genre annually. No one can read that much." - Tachyon Books' Jacob Weisman, interviewed in The Rumpus