Amazon popularised e-readers and they pretty much own digital publishing.
For normal users it doesn't matter that the books they buy from Amazon aren't epub- seriously do you think they even know what that means lol?
And for the rest of us Calibre converts anything in 30 seconds.
Wasn't that long ago that "Microsoft owned desktop computing". You couldn't do anything without Windows. Barely anything worked with Mac. Linux was just a baby.
The reason you fight monopolies, is because monopolies cannot last forever. There are all sorts of bad consequences with having digital publishing owned by a trillion dollar monopoly.
In order to have a free press at all, which is important in democracy, which is important for society to stay resilient, we need a diverse ecosystem of digital publishing options.
Calibre, with the DeDRM tools installed, is unreliable for Amazon's newest books. There are workarounds that involve getting the file in an older format, but then you lose the typography improvements that are only offered in KFX files.
It feels like Amazon is finally starting to close the DeDRM hole.
And for the rest of us Calibre converts anything in 30 seconds.