"As far as I am aware, nobody knows much about what traditional singing might have sounded like. There are discussions about this on Mustrad too. There are no recordings of it, obviously."

I find that an extraordinary statement. Obviously, we only have recordings from the time recording technology became available, but that takes us back to at least 1908 when Grainger recorded Joseph Taylor. Taylor was then in his mid-70s so he is an example of a singer from the second half of the 19th century. Grainger recorded a number of different singers and musicians at around that time and the British Library has 340 of his recordings.

Percy Grainger collection

We have all the volumes of VoTP, as well as other recordings by Topic, Leader, Veteran, Mustrad and other labels which cover the 20th century and right up to the present day. These are just examples which are commercially available, it doesn't include those in private collections or libraries. If you don't regard them as "traditional singers" you obviously have a very different idea of what that means than I, and I believe most others, do.

If we are to have a meaningful discussion, will you please explain what you take "traditional singer" to mean, and why the recordings I have mentioned are not of traditional singers?