I've always felt like the reading apps that are connected to eReaders (Kindle, Nook, Kobo, and now Sony) were seen by the makers as a kind of "gateway drug" - get folks hooked on eBooks so they'd want to buy the Kindle/Nook/Kobo/etc device as well - even though the real money is in the books themselves. Otherwise, why not make them more like the independent reading apps like Aldiko, Bluefire, Stanza, and best of all, the brilliant Marvin. Heck - Amazon could've turned Stanza into the Kindle app, but alas they chose not to.
Ah well, I'm grateful for Marvin and my Mini. And Calibre, and Dropbox.