Actually they did. Ebook prices dropped everywhere but Amazon.
Wow. Are you so enamoured with Apple that you have to deny inconvenient facts? From the first paragraph of TFA:
A federal judge on Friday approved a settlement in which Apple could begin paying $400 million to as many as 23 million consumers related to charges that it violated antitrust law by conspiring with publishers to raise e-book prices and thwart efforts by Amazon.
See that? It says "raise ebook prices".
I am constantly amazed by the number of people on