To be honest, I'm not all that surprised, by now. I had high hopes for that type of device, but even though screen resolution has been improved dramatically, and the frontlight has improved the grey-screen problem a lot, the fact still remains that the e-ink screen industry has basically failed to improve the low contrast problem. And why I am not sure, if that's the screen's fault too, but it remains that when you get used to modern fast tablets, an e-ink device moves like molasses in comparison. It's just not a pleasure to use, some feel.
Also, it seems that most people, including myself, really don't have much of a problem with reading on the tablets' backlit screens, especially since they became high-rez, so for most people e-ink readers really has nothing to attract them. They aren't even the cheapest readers now, so for many, the only real advantage they have is that they are the best for reading outdoors in bright light.
Re the new line of Fires, I'm sure they are good, but it's clear that the ambitions Amazon had for them of "selling premium devices for non-premium prices" (to quote Jeff Bezos) have failed (the Fire's market share being surprisingly disappointing), and so they have been modified sliiiiightly to: "selling pretty decent devices for rock-bottom prices". And admittedly, that often has an appeal too, even though I'm rather disappointed that they removed their flagship line, the HDX tablets, with their super-high-resolution screens, best speakers, etc.
[Update: I know have the new Fire HD 8. (Not the cheapest model, it's about $170 at 16 GB storage, very reasonable.) And it's my pleasure to report that despite the technically lower screen resolution (pixels per inch), I can not, even with a reading magnifier, see any difference in the sharpness, from the HDX! The color is even slightly better. And the speakers are the same, except they go a bit louder... It's a notch more elegantly designed, and it's cheaper. Well done Amazon.]
But now ebook-phobiasts has to find other excuses not to try ebooks out, because the entry level Fire tablet ("Fire 7", no hd) now costs only fifty dollars. FIFTY BUCKS! That's meal-and-movie money, for the small tech miracle that the tablet is. I think if you can't afford fifty dollars for a tablet (and get access to over a million free books of various kinds on the net), then you can't afford to buy very many books either.