All of this has been (until quite recently) purely a social construct, though. In the days of buying CDs, you were buying bits etched onto a plastic circle and you had physical possession of those bits. On Steam, you're literally buying bits, because you pay and then you download bits onto your PC (in this case, hypothetically Steam could decide to revoke future access to those bits, but you'd still have local copies of them).

Imagine if someone told you "Oh, that physical book you bought, with the pages and the words in it? Yeah, actually what we sold you was a license to a book." It's nonsense. We only played along in the digital realm because it was the only way for commercial digital artifacts to exist given the greater ease of making perfect copies of digital artifacts compared to physical artifacts like books.

That said, XaaS is now making that social construct physically real. It's still hamstringing one of the best things about digital artifacts, but at least it's honest now.