1) Amazon bundling a video service with their free shipping program.
2) Amazon's proprietary software locking in you into whatever platforms that are in their business interests.
3) Panasonic's proprietary TV platform that people can't be bothered to develop for.
4) Digital Restrictions Management that prevents one from downloading a movie via Amazon Prime and playing it in any other video player on any other platform.
This is just the usual awful situation when you rely on proprietary software. Stop using Amazon Prime to watch videos. Write to them about the problems you have. I recently wrote to Audible because their ebooks come with DRM and cannot be played on GNU/Linux using Free Software.