You need high volumes to drop the price and you can't get high volumes with high price. The E Ink technology has a lot of downsides compared to OLED and LCD, such as update speed, limited colors,...
We (http://www.visionect.com) have been building E Ink solutions for past decade and we just stoped convincing people that they should use E Ink where they could use LCD or OLED. E Ink is useful only as a niche solution for specific, mostly not consumer (exception being Kindle and Remarkable) products. We've sold a platform for any application and after a while we saw that it only makes sense to focus on specific niches (digital signage, transportation, bus stops) or go for finished product (see our https://getjoan.com).
In the end it is what it is - everybody says they'd use an E Ink display everyday, but almost nobody is prepared to spend the cash when they can use iPads, phones or huge LCD/OLED instead.
E Ink will have it's day in digital signage as they solve the colors as these screens will replace all paper advertising eventually, but untill the you'll see this screens on ebook readers / note takers, on conference rooms and on digital bus stops.