> The issue is with how the eink display is not fundamentally not suitable for a format that relies on scrolling more than reflowing.

I'm trying to understand your meaning of "format that relies on scrolling". How can this be the case since pdf was designed for printers?

"A PDF file is actually a PostScript file which has already been interpreted by a RIP and made into clearly defined objects.

Postscript is a file format supported by almost all high-end printers and many business-class laser printers. With these printers, you can simply send a postscript file to them over USB—no drivers required—and they’ll print it perfectly.

"

I will try to explain. Files meant for printing are typically created with a resolution target of 300dpi or above. There could be some fine details that are harder to see at normal reading distance, and this is easily solved by bringing the pages closer to the eye.

Files meant for screen display used to be standardized around a 72dpi resolution. Any detail not visible at the normal viewing distance is lost unless you are able to re-render the file at a higher resolution a.k.a. zooming in. And once you start doing it, scrolling becomes necessary in order to read through the document since the formatting is fixed or as you say "made into clearly defined objects". And this often works very poorly due to the inherent limitations of eink display when it comes to frequent screen refreshes.

Nowadays most displays, big or small, can do better than 72dpi but they still have a long way to go before they could match printed material.

Small screen e-readers get around the problem by aggressively reflowing the text of books with larger, sharper font and more line spacing to improve readability . Yet non of these techniques really work for PDF. Kindle DX failed rather miserably in the textbook and technical document market because of its limited resolution. I do not own the Kobo Elipsa, however I have spent some time with a couple of Dasung eink displays of a similar pixel density. And my current personal verdict is these panels are still not good enough for reading pdf files.

I don't know dude, I bought a Kobo Elipsa and finally I can study from my maths and physics textbooks that only come in PDF. I agree with you that it's terrible for reading in random access mode stuff like documentation. But for linear reading like literature or study material it's just wonderful.