If there were no 'source singers' such as were collected from by Sharp and others had the old songs all been forgotten or, in "the land of song", were they still so widely sung (and maybe written down) that the concept of a source singer was not relevant except for singing style?

The video linked above (https://www.youtube.com/watch?v=xoRdSkJLAfw) has a short section of a pre-WW2 recording of a performer singing 'in his own voice' and then in the style he remembered from his family.