Bluegrass, emanated about late forties early fifties.[Hardly contemporary jazz]
Flatt and Scruggs described their music as folk music with an overdrive[circa 1965].
perhaps there are different styles within bluegrass,but BillMonroe,Flatt and Scruggs,were not in my opinion influenced by JAZZ.
Earl Scruggs may be more recently Showing JAZZ INFLUENCES.
All this might indicate that a music as boring as Bluegrass ,progresses,from three chord pyrotechnics,and changes over a period of fifty years,thank god for that.
I would still prefer to listen to Roscoe Holcomb,Frank Profitt,Clarence Ashley,than to BillMonroe,Flatt and Scruggs.To me that kind of Bluegrass,Lost all that was appealing about old timey music,replacing it with an obession with right hand technique[forward rolls, backward rolls, sideways rolls]at the expense of subtlety ,feeling,soul,.
musical mathematics,an obession with technique at the expense of soul.