Looks like I may have spoken too soon about ebooks not catching on in the U.S. According to the International Digital Publishing Forum, U.S. trade ebook sales broke $8 million in the second quarter of 2007, up from under $2 million as recently as the fourth quarter of 2002. And that "does not include library, educational or professional electronic sales." It's still peanuts compared to print publishing revenues, but it's a sharper upward trend than I thought.
This is why one should always check the numbers and not just believe whatever the conventional wisdom is on a subject.