Captain Birdseye,

IMHO, virtuosity seems to be more of a concept that's related to classical or jazz performance. Folk music doesn't require it.

Virtuosity for its own sake is almost always boring. Pyrotechnics on an instrument means nothing without the expression and feeling of a musician.

It also requires a kind of musical originality of ideas. You could say that Earl Scruggs represents this since he was an innovator. Nowadays, there are so many bluegrass banjo players attempting to play like him that his playing has almost become cliched.

Still, when you listen to Scruggs participating in his bands, you get more than just virtuosity. He integrates well with other bluegrass musicians.

Not every kind of music will appeal to all.

Showmanship is relative depending on what entertains an audience. It can be very subtle in the hands of a great artist. If the music impels you and pulls you in, that's showmanship. The concept of "show biz" has changed over the years. The old stereo-type of the Song and Dance Man is now a cliche. People are entertained by other things.

However, when you listen to classical soloists, a certain amount of virtuosity is expected. I think the same applies to jazz.

As to instrumental virtuosity in folk music, it's really not that important, Doc Watson notwithstanding. Burl Ives, the great popularizer of folk music started singing songs with almost minimal but effective accompaniments that pretty much any player could do.
It didn't matter that he wasn't a virtuoso guitar player. If he were to come back and appear again on the concert stage as he did in the Forties and Fifties, he would have enthusiastic audiences that would love what he did. And the guitar would just "um-plunk" along.

Frank Hamilton