[fjtorres]

Folding displays will never replace rigid plates...
...but that is because they're not intended to.

If you're happy with your current rigid plate there is no reason to move to a more complex and more expensive device that isn't meant for you anyway. Folding displays aren't meant for every single user and every single use case but rather to address very specific and very real needs.

The primary market for folding displays is people who need a tablet but can only carry a phone. Or need a laptop but can barely carry a tablet. They will be neither cheap nor terribly large for a long time. As with most premium devices some will buy them as a novelty or a status symbol but the bulk of early buyers will almost certainly be the Road Warrior business types. Once the technology matures it is more likely to migrate upwards to ruggedized industrial niches than to low end consumer gadgetry.

If prices do come down the tech may show up in a foldable gaming unit ala Nintendo Switch and in laptop-class computers that are scaled-up versions of the renders in the Intel patent above.

But dedicated ereaders?
Nope.
That market isn't going to jump at 4-digit gadget prices any time soon.
(Notice that none of the folding phone hype even speculates about pricing. It won't be pretty. Main questions is whether they'll be closer to US$2000 than $1000.)

Foldable displays may be used for ereading here and there but they will be bought for other purposes, like most phones and tablets. It's interesting technology but for now it's a sideshow as far as the ebook world is concerned.