Given that E-Ink just announced their first loss in 10 quarters and a 54% drop in revenue I'd say Amazon doesn't have a lot of room to grind them lower on the screen price.
http://www.taipeitimes.com/News/biz/.../27/2003531343
It is also worth noting the following “Our major customer was too optimistic about its sales in the fourth quarter of last year and ordered too much from us,”. Sounds like demand is off, so economies of scale won't continue to drive down pricing. I wouldn't count on seeing significant price changes in the near term, unless Amazon decides to make a significant loss on each unit in order to stimulate demand.