From one perspective, "Jesse James" (..."had a wife to mourn for his life") in the abstract is "traditional," whether somebody makes a few changes or not. (Isn't that what traditional singers do?)

But legally, a specific copyrighted version is *not* traditional by virtue of being protected by copyright.

Example: When Steeleye Span creates elaborate folk-rock arrangements of traditional songs, those songs remain "traditional" in the abstract, but none of the new, copyrighted arrangements, as a specific piece of music, is "traditional" in any sense.