My Kindle doesn't show ads, because I didn't buy the version that shows ads. I have never had a book deleted from my Kindle by Amazon.

There was a single instance of a couple of George Orwell's books being removed from user devices in July 2009. Customers had the purchase price they paid refunded. It was done because the company selling those books didn't actually have the rights to sell them. Afterwards, Jeff Bezos apologised and described it as "stupid, thoughtless, and painfully out of line with our principles". It is therefore unlikely to happen again.

Given the commercial structure of Amazon e-Books, does it make sense to buy something that gives you as a reader more rights (e.g. when you die)? Perhaps. But I know what I've got into, so has every other Kindle owner on Earth.

You do you, but your stated premise against Kindle is at best a little inaccurate and outdated, and at worst comes across perhaps a little hyperbolic.