"Others" were doing it. Bill Monroe put a new "face" on it and created a style, by which most other bluegrass has been played and sung since that time. And yes, that high lonesome sound. I think pre-bluegrass bluegrass is what we most often term "old-timey" today. Just my opinion.

Terminally ill with bluegrass fever and a sucker for a good flatpicker with a high lonesome sound in his voice ...