The music moves where it wants to. I've been at eclectic acoustic sessions recently with very good young players (fiddle, guitar, melodeon) and singers. Pub open mics in this area (Sussex) are mainly people in their 20s and 30s. Some club occasions are predominantly 40/50+ audiences - but at least two clubs I go to are run by people in their 30s and attract a very mixed age group. Some local Irish sessions have young demon fiddlers attending. The scene changes but the music will remain - changing here and there, perhaps.