[Quoth]

Likely the USB idea is stupid, though maybe an option for older ereaders that ONLY have USB, or maybe USB + SD card but no WiFi.

I'm only musing on the basic problem of how does a random bookshop sell ebooks in store. Selling an ereader isn't viable for most and even a Kindle can still be used to read books not bought from Amazon, they'd not risk disabling that unless all other ereaders are gone. Also the unrelated issue of how do people with no internet (or clueless) register and put content on an ereader.

Should forced registration be illegal? Maybe it actually is in EU. The fact that you can use a fake email on Kobo or there is a way using gift voucher on Amazon is irrelevant, you can't setup the Kobo or Kindle without an Internet connection to Amazon or Kobo, using WiFi or a computer App. My dad had to take his Kindle back to the shop to get it registered as he had no idea how to use his WiFi. He does have a computer on broadband, via a cable to the Modem.

Without someone doing something smart there is only going to be Amazon, the Kindle and Kindle apps. Maybe then they'd stop producing Kindles and only provide the Kindle app.

Is there any reason why NO eink reader other than Kindle has the Amazon app, but phones & tablets do? Or is there such a thing officially? Obviously Nook and Kobo would have no interest unless Kindles had ALSO built in Kobo and B&N storefronts as well as Amazon. That won't happen ever unless there is a law like the MS Browser Choice, which either no longer applies, or MS has forgotten.