US Supreme Court rules for Google over Oracle

Licences are not "transfers" of copyright, not even temporarily: only the copyright holder has the right to licence the work.

Yes and no. An exclusive license looks a lot like a temporary transfer of the property, especially if it comes with sublicensing rights. I think this gets at a bigger reason our legal system tends to look at things like copyright as forms of property: it's a useful abstraction. Just as Unix treats all kinds of things as files, even when they aren't, the legal system treats all kinds of things as property even when they aren't. Our legal and business systems are built around the concept of property, and they've spent centuries learning how to reason about it. Treating more and more abstract kinds of things- contracts, obligations, debts, government granted privileges, or what have you- as property lets lawyers and business people apply those centuries of case law and business processes to them. Even if the abstraction is imperfect so there need to be new principles added, like fair use for copyright, starting from well established principles means they aren't inventing everything from scratch.