So - Dave is right really - folk clubs as they stand are not going to be attractive to most young people. But then they are not attractive to most older people either. We are a minority.
The question is whether we should be worrying about it.
I am a member of the local canoe club - and we don't tend to attract a huge amount of rowers to our club. That is because we like what we like, and they like something different. They have their club, we have ours and everyone is happy. Young people will go to their own kind of venue, start one if they want to, not if they don't. The music is not going to die out, even if all us old fogies drop dead one by one & leave the folk club dwindled down to nothing.
So what is it we want from these young folkies? Are we wanting to pass on the old trad baton? Or are we getting bored with our own format and wishing someone young & vibrant would come in and liven us up? In which case I wonder if the real point is that we just need to inject some energy and passion into the clubs and make them somewhere WE want to be, instead of worrying about trying to appeal to the rest of the populace.