See? And everyone says that the publishers aren't learning from what happened to the music houses. This shows that that just isn't true. They took a very valuable lesson away:
"Don't let people come to accept as reasonable a lower price than you want them to."

This seems mighty similar to what happened a few years back with the music factories on one side and some little company called "Itunes". Once Itunes had established a lower (and consistent) price point consumers started to reach the consensus that it WAS the correct price. When the industry tried to split off and (eventually) start offering the music online at fluctuating prices (often between $1 to $3 a track) they found themselves with empty storefronts and unable to reset customer expectations.

This same situation could be applied to Amazon and ebooks. As more people become used to ebooks (and the Kindle especially since it always seems to be trotted out as the representation of a dedicated ereader) they will come to see 9.99 as THE price a book is supposed to be. Wait to long and it will become the standard price. Something the pubs probably won't want to see.