Sure, DarkScribe, the current Pearl display is functional, but so are the displays on the iPad 1, and the archaic Sony PRS 500. Technological advances are often not based on necessities.
I have no problems reading the text on older E Ink displays, but if I could have a choice between the Pearl display with 16 shades of grey, and the 505 display with 6, I would choose the device with clearer, sharper, more paper-like contrast every time. Technology is all about progress, and E Ink reader displays have made none. The focus of E Ink should be on making displays with whiter backgrounds, higher pixel density, and more shades of grey if they want to compete with tablet popularity. E Ink displays have the ability to look outstanding, rather than satisfactory.
Also, if eReader companies are going to upgrade their devices, wouldn't common sense dictate that the screen resolution should update as well? Should we just be "satisfied" with our devices, or should they continue to improve, regardless of need? The iPad 3 didn't need
to feature a retina display, but I can't believe you would think it unnecessary after viewing text on it.
And I would disagree that "no one is complaining about it," many tech bloggers and eReader enthusiasts
have been griping about lack of display advancement. That's why companies like Onyx Boox are developing HD readers like the i62 HD in hopes that they can generate business from readers who are dissatisfied with the status quo.
Is it disingenuous to expect an upgrade after 2.5 years? You must not be very familiar with technology standards.