While Amazon does some shady stuff, at least _some_ of the blame here belongs on the big publishing companies.
One of the big publishers put heavy pressure on Amazon to patch DRM exploits or else they would pull all their content from the platform (or so I was told).
(I worked at Kindle 2017-2019, and was on the team that wrote the code that OP reversed engineered)
One argument I heard was that this was actually due to "kindle unlimited". I think publishers didn't really care that people were removing drm after purchasing a book, but with amazon's push to a streaming model people started subscribing and mass downloading books to read after unsubscribing. Both unlimited and book purchases used the same drm.
Maybe streaming is inevitable, but streaming is at least partially pushed by the streaming services who make more money on streaming than they do purchases.
Books are rapidly dropping in relevance. It could certainly be that that's exactly how this went down a decade ago, but I'd be willing to bet on Amazon stipulating "no DRM to be on Amazon" (not just Kindle; bundle all the first party distribution together) now and at least some of the big houses folding.
Reading is still a completely different thing from a book, a stream of consciousness between a writer and a reader, than it is reading in almost any other format. The way we read online from websites and apps is changing how our brains work and how we process text for information (not for the better). We're slowly becoming like the look-up tools that we use in Google and other search engines and LLM agents.
The best way for many chronically online dopamine fried people today to revert their brain back to some normality would be for them to read books and to fight through the distractions as they read.
There's plenty of blame to go around. Tech companies like Amazon blame publishers or other tech companies, publishers blame tech companies or other publishers. My point is that DRM has gone from bad to worse.
So... It's your fault? I mean, you wrote it. You had the option to say no. You didn't. Tired of programmers making the world worse and trying to blame everyone but themselves for why the world got shittier.
One of the big publishers put heavy pressure on Amazon to patch DRM exploits or else they would pull all their content from the platform (or so I was told).
(I worked at Kindle 2017-2019, and was on the team that wrote the code that OP reversed engineered)