Shanda recently cut the price of their Bambook ereader in half. This 6" E-ink, Wifi equiped ereader is now selling for only RMB499. That's $74 USD, and so far as I know that's actually less than the cost of the components.
Hanvon have also cut the price of a number of their ereaders, with some models now as low as RMB 599 ($92 USD).
If I had to guess, I would say that Chinese ebook readers are facing fierce competition from cheap tablets and handhelds. It's not the same in the US, where we have 2 giants fighting. In China there's hundreds if not thousands of small companies trying to produce gadgets as cheap as possible. It's quite clearly driving the prices lower at a faster rate than anywhere else.