I know about 'incremental repetition', rather like 'repetition with replacement'. That said 'milk white steed' is not an example of that phenomenon.

Why have I asked for information about Bronson's methodologyy and aesthetic principles? Well, first, why not? And second, it seems reasonable to me to think about the reliability of anybody deemed to me an authority. As I have tried to suggest before, quite a bit of work on 'folklore' seems to me to be based around uncritical acceptance and repetition (and yes some of this may even be incremental repetition, let's face it 'history' is a narrative like all the others) of what turns out to be relatively broad conjecture. Nothing wrong with conjecturing and using one's imagination, but helpful to be able to tell, for example, information derived from primary sources from other sorts of of stuff.

By the way, I deliberately stated not that Walpole's was the first version ever but that it is seen as being the earliest known (and we have to accept that he was right about when he first heard it).

Regarding Bronson, it doesn't matter how many tunes he gives for the song, the aesthetic points I made, and that I understand Child to have made, still stand.