You're not doing the right thing if you're helping to enforce DRM. This removes power from both authors and readers to Amazon's benefit. If you want to do the right thing, buy a physical book and then pirate the ebook.
Clearly there are already ways to remove the DRM, and the lifespan of a Kindle is decades so they will not easily be able to add new DRM to the old hardware.
In my opinion, it's roughly analogous to Steam but it moves at a glacial pace.
The revenue gained from those devices is likely greater than the revenue lost from people pirating content who would actually pay for it.
There are blu-ray players which support Amazon video and they can not be updated by Amazon.