I'm surprised that this is being dropped, but the "Send to Kindle"[0] feature is still supported. I would imagine that the email servers (and whatever other behind-the-scenes cruft it requires) to relay files to individual Kindle devices is a much bigger maintenance burden and "piracy" enabler than transferring via USB.
I'm a huge user of the Send to Kindle feature via my Calibre library too, so this has me pretty bummed and pessimistic for the future. I guess if the worst comes to pass, I can just look into jailbreaking or getting any of the zillion other Android-based eReaders from AliExpress.
send to kindle requires that you connect your kindle to the cloud, which gives it a chance to sync up all the data the device has collected while it has been offline.
it seems pretty clear that's what's really important to them - they want all that sweet sweet telemetry, and could care less whether you're actually buying the books or not.
Sure, I read that in TFA too. My point is that if USB transfers of Kindle eBooks are being sunsetted, I would estimate that Send to Kindle's days are also numbered.
The "Send to Kindle" has a hard limit of 50MiB if done via Email, or 200MiB if done via amazon.com/sendtokindle.
My complaint on this feature is mostly that the only supported proper ebook format is now epub, and I frequently run into the E999 error. Sometimes I can workaround it by converting the epub to mobi and back, but sometimes it just keeps failing which is frustrating.
(I run Calibre on a Linux headless box in Docker so connecting it to USB then transfer is toily)
I'm a huge user of the Send to Kindle feature via my Calibre library too, so this has me pretty bummed and pessimistic for the future. I guess if the worst comes to pass, I can just look into jailbreaking or getting any of the zillion other Android-based eReaders from AliExpress.
[0] https://www.amazon.com/sendtokindle/email