>An even easier fit would be comic books.

That's just a book format issue, but I'm on board.

>They already let you steam libraries of photos.

Well, about that... they're kind of shit at it. Photos have always been their least favorite supported media. Not much in the way of metadata support, unable to organize them. But it brings me to another problem... they don't understand what media types are.

They support audio, but call it music. This means, just for instance, that there's a shitty icon for the library... I made a comedy album library, Plex. Steve Martin the banjo player and Steven Martin the comedian are the same human, but I don't want one album recommended as related to the other. And I don't want to see the little music note icon for the library either. Think of audio as "audio that can have many types" rather than music. It's the same with images... what if I want to have a library full of van Gogh's works? Why are you trying to mix these in with pictures of my nieces?

>Also, they could handle audiobooks since they already stream music.

But they can't, not really. Because they think all audio is music, their interface doesn't handle it... no one wants to randomize the play order of the chapters of a book. And they'd actually like to keep a bookmark of where they stopped listening. But because "all audio is music" their model is fundamentally broken.

>When I use my e-reader, I like features like highlighting, taking notes, dictionaries, and other features that are more complicated that just streaming rendered images from a book.

Well, if they implemented it correctly, it wouldn't be exactly "streaming images from a book". And they already do stuff with related media in a sophisticated fashion. If you want to see the trailers and making-ofs for a a movie, those are available right from the menu. Dictionaries or highlighting or note-taking just isn't that big of a deal. They could do it, they don't want to. They'd rather be a streaming service.