Good question, TE. I'm not sure, but according to Billie Holliday, whatever/whomever Shane was a metaphor of, it/he was never coming back. Do you know the story? Billy Crystal, whose uncle owned Commodore Records, tells of being 7 years old and sitting on Holliday's lap as they watched Shane together at the movie theatre. And at the end, when Shane is riding off into the sunset and the boy Joey is yelling out "Come back, Shane!", Crystal remembers Holliday whispering to herself "No, he ain't coming back. Uh huh, Joey, Shane ain't never coming back. He's not that kind - he's gotta keep roaming. Bye, bye, Shane".
Peter