This may change over time, as other e-ink-alike technologies come online, but it is the current state of affairs, and it's why everything is in such a narrow price band.
Buying "open" e-ink reader devices isn't that hard: just about every but the kindle has .pdf compatibility, for example.
There is no "open" ebook format the way .mp3s are "open": all major publishers that sell ebooks sell in drm-ed formats, and only independents and small-timers and oddballs sell legit content in unprotected .pdf.
Edit: http://www.pvi.com.tw/en/index/index.php is PVI.
-----------------------------------------
The Project Gutenberg "Top 5":
The Outline of Science, Vol. 1 (of 4) by J. Arthur Thomson (531)
Manners, Customs, and Dress During the Middle Ages and During the Renaissance Period by P. L. Jacob (453)
Pride and Prejudice by Jane Austen (324)
Illustrated History of Furniture by Frederick Litchfield (303)
Searchlights on Health by B. G. Jefferis and J. L. Nichols (270)
-----------------------------------------
The Kindle "Top 5"
The Last Olympian by Rick Riordan
Liberty and Tyranny: A Conservative Manifesto by Mark R. Levin
First Family by David Baldacci
The 8th Confession by James Patterson
Dead and Gone (Sookie Stackhouse, Book 9) by Charlaine Harris
It would have a tough time being a sustainable business given the costs of prototyping, making deals with wireless providers, etc. and the alternative of just offering the device just doesn't seem worth the time.
The wireless thing is cool, but ereaders existed for a long time without them. I think it would be cool to have whispernet, but it is by no means essential to the enjoyment of my ereader. The next gen bebook will have wifi access to read rss reads etc. as well.
I guess someone did. :)
Although, I got the Sony when it first came out ( the lack of DRM in it attracted me) I am very satisfied with it