i have been singing in folk clubs and been going to folk clubs since 1967,
my experience is that the decline in folk club attendance on seperate rooms was a gradual thing, but fairly noticeable in 1983 compared to 1973. the uk folk scene appears to be healthy according to steve gardham who has quoted all the extra outside events that are still happening and were happening back in the early 80s
such as singers going in to schools folk clubs happening in pubs sessions happening in pubs, none of which suddenly started happening since jim left the uk in 1996