Malcolm, yo' de man! You hit the nail (several nails) right on the head, and far more eloquently than I can. Seems as though ageists, by promoting the 'Yoof' culture, are attempting to take over the folk scene in exactly the same way they're taking over everything else (fashion, commerce, industry, you name it). The folk music scene's a broad church in which everyone, irrespective of age, should be treated as equals and granted the same respect as performers.
Encouragement of youngsters is vital and is to be applauded, but it shouldn't involve putting them on false pedestals. And there are some good tunes played on old fiddles (as me old mam used to say).