Liking music from other cultures is always, I suspect, going to be a minority interest.

That is true enough - but for most English people (white or black) traditional music is "music from another culture". That includes most people who have learnt to enjoy it and who are carrying it on.

For very many people their first exposure to traditional music will in fact have been to music from "other cultures" than ethnic-English , such as the varieties of American, Irish and Caribbean music and dance.

That then can lead on to a curiosity about and an exploration of the music of our ancestoral group, wherever they may have come from - for some people that would mean ethnic English traditions, for other it might mean African or Indian music, or Klezmer or whatever.

Folk music is always balanced between reinventing itself in each generation, open to a variety of influences, and preserving and respecting the link with the roots, whatever those roots might be.