That hasn't been my experience. YMSB because of their "jamgrass nature" skews toward the college demographic; however, I see a nice mix of ages at most neo-bluegrass/Americana shows. Audiences are pretty mixed. That being said, I am almost always the youngest player at most of the jams I attend... most of the musicians at those jams are 40s to 50s, with a few 60+.
Understood, there are a lot of bluegrass shows and venues I have not been to so my personal experience is narrow. I did go to one festival in Guthrie Oklahoma once that had all the very traditional groups with traditional audiences and then this Czechoslovakian Bluegrass band that had a trap drum set and electrics and did a version of "Wild Horses" that was very bizarre and extremely entertaining. I bought a CD.
MY GAWt, deyr yoozin moar dan wun MYKE! :***: Blasstpheemers! Wuteffer happ'n t'dem gutten ol' daice wen der moosishuns gaddered 'rownd wun Myke? 

