> when you "buy" a movie or book on Amazon lets say, you're just buying a license to that product

I have never seen an ebook product entry containing the word "license" in the name or description. And even if we assume that's fine, that still doesn't warrant taking away access to the product you bought. If you buy a DVD and stream the movie online you won't get raided and have all DVDs, CDs, vinyls and books taken away. Apple, Amazon etc are doing exactly that.

Imho it should at least say "buy license", or ideally: "rent for an unknown amount of time, do you feel lucky?"