There was the assumption that literary fiction requires the traditional paper format, and would only be accepted by its readers if this was adhered to. Genre fiction, on the other hand, was considered far less lofty (even though it outsells lit fic by the shed-load) and therefore it was thought permissible for this to slum-it on ereaders.
Remember twelve-track cassette tapes? Remember those 1" thick tapes on whopping great spools? People used to say CDs would never replace these, as CDs were too expensive and people who had accumulated big music collections would be reluctant to change formats even though the sound quality on CDs was better. Some people still had those brittle 10" discs which played crackles at 78 mph. Wax cylinders - let's not forget those! Or those scribes of old who'd sit in a market place and offer to write letters or copy scrolls in return for a shekel or two; they probably told their clients that those new-fangled printing presses wouldn't take over from their traditional role.
I think the changes in music formats are a good indicator of the changes happening in publishing. Most people under twenty apparently prefer to download music in digital form rather than buy a CD. They have cast off the desire to own big collections of physical objects (CDs, vinyl albums) in favour of portable, cheap formats. People buy only the tracks they like, instead of whole albums which have maybe five or six good songs plus a few pot-boilers. And if you're a student or someone who's living in a
Similar principles apply to books. There will probably always be a place for large-format art books, simply because people like looking at big pictures. On the other hand, once the technology improves and images (and text) can be projected like a holographic cinema screen, then this may not be an issue either.
Fads die out because they don't work well, or because their scope is limited. Ereaders, on the other hand, seem highly likely to keep getting better as with all technology.
Years ago, I used to work in Liverpool City Library. One of my jobs was to retrieve old books stored in the vast stacks. There were literally thousands of books there, on shelves inaccessible to the public. Some of these books were highly valuable, worth more than most people's annual salaries. Others were worth no more than pence, if their market value was the only value ascribed to them. These books were kept for reference only, and had to be read at the library tables. Now whole libraries like this can be carried round on one small gadget, accessible to all at any time. If you consider that knowledge is power, isn't this more powerful?