Technology

there are newer eink tablets out there, but they tend to be bigger, heavier, and more expensive.

A kindle (and similar devices) are cheap, and light. great if all you want is to read on them.

Eink, gives you long battery life and it's easier on the eyes.

No, but Amazon's are very often the cheapest by far, easiest to find used (since more are sold in the first place). On Prime days they're often very cheap.

I imagine most of the profit comes from buying/renting the books.

No. But they're really inexpensive and link up to people's Amazon accounts so it's easy to manage your books, if you are a person who likes to use Amazon for that.

I've had two Kindles, the first was before they had touch screens, and I loved it (this was a long, long time ago). Even with the hard case eventually I broke the screen after many years of travel and use, and hated the one I replaced it with. Awful piece of garbage, I wanted to return it and get one with physical buttons but they didn't make them any more and I was too lazy to do second hand searching. I've never used Amazon to buy e books but I got a lot of free ones over the years (mostly cookbooks) and it was handy to be able to just download them directly to the device, but I prefer to manage books over USB and that always worked fine.

E-ink is amazing. Battery life lasts for ages, which really is what you want for a dedicated reader. There's other types on the market, but it's hard to compete with Amazon's prices and feature set - especially because they sell ones that are ad-supported and that REALLY drives the prices down for people that are willing to have their lock screen be an ad that goes away when they wake the device, which is an easy compromise for most.

My Kindle just collected dust now, I use a supernote as a note taker and I use it for ebooks also. It was about $500 USD - granted it does way, way more than a Kindle, but yeah. I could probably get an ad-supported Kindle for 1/10 the cost, maybe, not sure what their prices are these days. Not saying that competing dedicated readers are in that price range, they're not, but Kindle dominates the market due to brand recognition, advertising, and as far as I know they were the first to really offer a product like it in the first place so they'll always have a big piece of the market, like iPods did in the MP3 player space vs objectively superior competitors that came after it.