Because it's not. It is trivial to buy a book on the Kindle store, and while it may be trivial to us here to go and pirate a azw3 and transfer it, it's not to most people

People always forget the pareto principle when it comes to anti-piracy. No, they don't stop everyone, but a minor hurdle stops a hell of a lot of "ordinary" people

annas-archive.org, search and download, open it on your computer. functionally as trivial as purchasing a book on amazon. reading on a kindle is a niche case.