I love S & G but there is a difference between CD's and concerts.   Some groups like S & G are much better in CD.   Some groups I would never buy their CD, but enjoy them in concert.   

I go to about 20 coffeehouse and 4-5 folk festivals a year.   I also get free tickets to about 40-50 rock concerts a year and go to 10-15. In the past few years, I have changed my mind about performing. I loved the "Discomania" show with Village People and KC and the Sunshine Band even though I would never buy or listen to any of their music.   It was hugely fun and entertaining.   Conversely, I go to many singer songwriters who sit in a chair and sing non descript songs.    Most of them don't draw me in.

I think part of the "performance" involves doing more than just "standing there and singing"   At most folk concerts you get the story behind the song and learn a little about the performer.   (that never happens at a rock concert)   Getting the group to sing or clap or participate is another part of performing.   Cape Breton fiddle players are very "showy" in performance and many step dance.   Other groups like the Arrogrant Worms or Barachois add theatrics and odd props.   There are many things you can do.   Art uses humor very effectively "folklore, jolklore, and corn" on his business card.

I think folkies should learn from MTV and the Rolling Stones.   Put more performance into a concert.   I don't think it has to take away from the music.