Authors exclusive to Amazon are ultimately working against their own interests. Amazon doesn’t care about them, can and has changed contract terms when they felt like it, canceled accounts etc. But I don’t see many authors moving from where the money is right now, long term interests aside. It’ll take readers to move but many readers have also shown they don’t care about authors, they just want their hard work as cheap as possible. It’s a race to the bottom fueled by authors and their audience.