It’s also possible that people who read on these devices aren’t tech savvy enough to care about how awful of an experience it is.
Absolutely.
Some people who don't quite "get" computers seem to find it really difficult what they should expect from a device. They can have a laptop that needs 5 minutes to boot and a broken mouse that jumps to a random location on the screen once every minute, and the only thing they'll complain about is that Windows doesn't let them select a lot of files properly(because the mouse jumps around like crazy).
The skit in IT Crowd with the "laptop from the exorcist" is sometimes more accurate than one might like.
People want a cheap device that doesn't ruin the reading experience and has access to all the books they want.