What Everyboby said. Monroe was searching for a new way and had some ideas in his head, but it took the players to make it happen. The "Flatt" G run is present in Bill Monroe's recordings before Flatt joined the band. Bill was an excellent guitarist. Stringbean was an attempt to add the banjo sound to Monroe's evolving music. Bill also tried out the accordion (his mother played accordion as well as fiddle) with Sally Ann Forester on the box. When WWII ended and many veterans returned and war workers were freed from restrictions, fine musicians gravitated to Monroe and his steadily working touring organization. Monroe was an ornery driven person with musical ideas in his head. He attracted the greatest musicians, and they would stay with Monroe for two or three years. And become even greater. And move on. Being a Bluegrass Boy is a mark of distinction. Whether Earl Scruggs would have been as organized and great without his years in Bill's band is a forever open question.