I'm curious how much you think an e-reader should cost?
Let's say the BOM for a bargain-bin e-reader is ~$65: e-ink display (~$25), mainboard (~$15), touchscreen and/or buttons (~$7), radios (~$3), battery (~$3), case (~$3), assembly (~$6), packaging (~$3). Forget about a charging cable. Then you've got to iron out the drivers and software, provide support, handle returns (which will be higher if you cheap out on materials) and turn a profit (assuming you're not Amazon). Let's say you charge ~1.5x BOM, now your product is ~$98.
Maybe you "borrow" your software and hardware designs from a competitor. Maybe you're willing to continuously change your company name so you can purchase low-quality parts without having to accept returns. Maybe you ask suppliers for a discount because you just know you're going to have enormous economies of scale and you're somehow more convincing than every other company (that isn't Amazon) asking for the same discount.
You do all of the above so you can sell your new e-reader for the insanely low price of $80. Will you move enough units for all that to be worth it? Are there really that many customers who would buy your $80 no-name e-reader instead of a second-hand Kindle?