A last point (and THREAD DRIFT) I think as others have noted, there is a lot of ambiguity surrounding the catch all term 'folk club' which can mean different things to different people. Both 'Trad tune (and song) sessions' and 'singarounds' and other more formal pro. performance clubs, come under the umbrella term 'folk club'.

While Trad. tunes and songs are timeless, and thus of potential interest to people of all generations who want to sing/play Trad. tunes and songs - I think it's here you may see a greater likelihood of attracting interest from non 'folkies' and younger musicians.

'Singarounds' on the other hand, could quite reasonably be termed 'Sixties acoustic evenings' and as such will continue to be of interest to a restricted (and dwindling) demographic.

I think in the longer term, while Trad. sessions will hopefully continue to thrive (as indeed they seem to currently be doing), the 'singaround' type of 'folk club' (at least as we know it), is I suspect, less likely to survive beyond the baby boomer generation. I don't necessarily think that's anything to be dismayed by.

As for the professional performance club, maybe some will continue, or new ones attracting younger audiences will supplant them, but on the whole festivals would seem to be the way things are going where the younger crowd is concerned - and it's a lively vibrant scene, so I don't think there's anything to be mourned there either.