How is Amazon’s 2013 tablet still the best one it ever released?

It’s often posited that a major factor in the tablet market’s recent decline is a lack of reason to upgrade; most people use these devices for little more than content consumption, and the one they bought years ago will often do that job for years to come. I don’t quite embody this myself, as I work on my iPad Pro almost every day, but it’s not surprising to me either — I also still use my Amazon Fire HDX all the time.
The weird thing with Amazon tablets in particul