Oops, the Guest above was me. Sorry about that.

I can't really comment much on jazz, as it is not something I've been very involved in, except to say jazz was one of the genres I had in mind when I said "by no means all" have an authorative version. But again, speaking as a complete ignoramus on the subject, the impression I get is that jazz seeks to have an original performance every time, so to that extent it eschews the inheritance component of the 1954 definition as far as practical.

The musical theatre one is certainly an area I hadn't considered before, but I suspect there is still the authorative version, even if it is rarely performed. I'm thinking of the "I've got a Little List" song in the Mikado, for example, which has been updated with topical references from the outset so the original is probably almost never performed and in a weird way it would be less authentic to do so.

I suppose the concept I have in mind is best expressed diagrammatically. Some genres have a central core - the authorative version - and all around it are performances, which are versions in their own right, so can be used as further versions. However, the overall structure is of a 'dense bush' with lots of branches off the centre and nothing more than a few steps from the central core.   The 1954 definition has a thin, treelike structure, with comparatively few branches off the root, then branches off branches off branches off branches ...

And of course, reality is such that examples of everything in between can be found as well!