Mildly related side note: my Kindle DX died this year (it won't charge nor reset, even with a new battery) so I've been looking for a replacement. I'd like a second-hand one but, based on my eBay experience, barely anyone is getting rid of their e-readers.

Considering how many second-hand computers, tablets, and cell phones are there, I find this surprising.

Check out the Onyx_Boox subreddit. People often put their used Boox devices up for sale (presumably when they buy new ones).