Are there any instances from the closed e-book system (kindle, nook, etc..) where you paid for a book and the book was either updated to a revised version or just removed from the device because of the content in the book?
Kindle regularly removes sideloaded books if it decides you didn't purchase them from Amazon. Allegedly it's due to an incompatibility between the Kindle DRM and the way Calibre tricks the Kindle into displaying book covers for sideloaded files, but it's still annoying. The solution is to leave the device in airplane mode.
Yep. The infamous case in my mind were the Roald Dahl updates. I believe there were a few more cases that got news coverage a few years back, but I don't recall, so don't quote me.
https://goodereader.com/blog/electronic-readers/ronald-dahl-...
It's fairly rare - like when 1984 was deleted from amazon when the seller didn't have the rights (and customer was refunded), but https://www.theguardian.com/money/2012/oct/22/amazon-wipes-c... shows an example where someone's account was deleted and they lost all licenses of books they bought.
Are there any serious legislative efforts to fix the ebook market? I know getting rid of DRM entirely isn't likely to happen, but at this point I'd be happy with just vendor-neutral DRM.
There was that famous 2009 case of Amazon remote deleting George Orwell's 1984 and Animal Farm from Kindles.
Yep, first instance I know of was from back in 2009, https://www.theguardian.com/technology/2009/jul/17/amazon-ki... and the kind of thing keeps happening over the years. It'll continue to happen since you aren't paying for a book. You're paying for a license to read the book for as long as the publisher/owner allows you to do so and they can revoke the permission at any time.
I still find it hilariously ironic that the first instance that was widely reported (as far as I know) was it happening to 1984.