> I can buy DRM free music from the iTunes Store, download the files, and they’re mine.

If you hold the copyright they are yours, but most files downloaded from iTunes and similar services are unlikely to be yours. A license to use the content, even where there are few restrictions, is not ownership.

If holding the copyright is the bar, then physical media doesn’t give that either. Buying a physical book doesn’t transfer the copyright to me. I can start producing more copies and selling them, at least not legally.