Then I have to buy an extra Kindle while not getting a discount for buying the ebook, and I can only lend to one person at a time, and anyone I lend to has to be trustworthy not to make purchases on my account.
No, you do not have to trust the other person to not make purchases. You can simply set up the parental controls.
I understand why people are downvoting my original comment -- it is very easy to dislike Amazon, for many reasons -- but the fact remains that you can lend eBooks.
You just have to put them on a physical device first.
And you're allowed to put each eBook on up to 5 devices. That means you could, theoretically lend up to 5 copies at a time. Not just one.
I didn't realize that parental controls could restrict purchasing, but it makes sense.
It's true that you can lend ebooks, there are just a lot more hoops to jump through ;) I can't lend my ebooks, because I don't have a spare device, but that can be changed if I want. If I'm going to pay just as much for the paper book, though, I might as well buy that and skip the extra device management.
I absolutely hate that this comment is downvoted. This works, costs as much as a regular hard cover to setup -- $27, as someone pointed out. As the author pointed out - parental controls prevent any access or misuse. Hell, you can just not put your account on it, invite your friend to use his own amazon account and lend a book to him. Still, works just like a book. This fixes the only gotcha Kindle sharing has - you can only share with other Kindlers.
Just because it's not one's opinion, does not make a comment downvote-worthy.
That is not by design and there are numerous "gotchas" with that, like this third party using that Kindle to buy content on your account, changing your bookmarks, and so on.
It might work for "family sharing" (although Amazon actually supports that already), but for sharing with third parties it is risky in my opinion.
I've never done this (probably b/c it just feels weird to loan devices, while loaning books seems perfectly normal).
But you could be right, declining prices of gadgets and aggressive restrictions like DMCA, and in 20 years it might be the opposite, just far easier to trade devices rather than licenses.
Not that complicated. And you get to loan hundreds of books at once.