Like almost any field of research, there are various ways to do it. Child did his part, and partly in response to him, others did other parts...(often using Child as a jumping off point). I don't know that Bronson ever sang a song, either, but I'm glad he researched some tunes.

As has been said, it is pretty pointless now to be pointing out what he 'could' have done, or didn't do....

(and I have some serious reservations about the way the Lomaxes 'collected', but they DID the work, they did it their way...and I'm glad they did it.)