it is surely inherent in the 1954 definition that the members of the community participate in the delivery and therefore evolution of folk song - one of the main factors that distinguishes it from consumerist music.

But isn't consumerist music produced & determined by a community too? A community of writers, arrangers, producers, and artists shaping a traditional genre which is itself determined by historical continuity and broader cultural considerations, such as current trends and market forces. And can it be truly said that any musician is not a part of a community, even if they've learnt all they know from books and records? I think perhaps not.