Combined with the announcement that they're killing the old Kindles as well...this is 100% about preventing people from liberating DRM from their books. Full stop. They are closing each and every remaining hole.
I wonder if it'll actually work? At the moment you can pretty much go to https://en.wikipedia.org/wiki/Library_Genesis and download whatever.
Also, AI chatbots outright refuse to give any answer that is remote related to piracy (or any adjacent topics). Since they take over the role of search engines, that's also a big factor IMO.