I think IanC and others have a point. Folk Clubs are not exactly central to folk music nowadays. They had a crucial and central role in the folk revival of the 50's and 60's but but progressively less so since. They are wonderful institutions, but not the core of the music. And as IanC said, they were never anything much to do with "the tradition"(however you understand that term) in any case."The tradition" was the social force that made the songs and tunes, the folk clubs were meetings for people who liked the music that the tradition had produced, so we had get-togethers where we could perform and listen in a safe environment. I don't think anybody imagined the clubs were to be the centre of anything, they were seen more as incubators/seedbeds where music could be nurtured before re-release into the wild. The clubs also became a very good place for singer-songwriters to try out their stuff, but that is another story.
   I thought a bit of a statistical look might be interesting. I am actively involved as a professional musician in the palying and teaching of traditional folk music, and have been for forty something years, so I am probably a reasonable bit of litmus paper to locate where the folk action is. I've just done a bit of a classification of the last twenty gigs I've played with the Boat Band, and it makes interesting reading in the context of this discussion. They break down as follows.
4 pubs
3 Private functions(birthdays/weddings)
3 Community events
3 Folk festivals
2 Other festivals
2 dances
2 Unclassifiable arts events
1 Folk club

That seems to me to show that we (and therefore the folk music we play) are getting to quite a broad range of gigs.It also shows that only one gig out of the twenty is a folk club, which suggests that the clubs are not that crucial a part of the general folk scene nowadays. A significant part, certainly, but minor. I live in a medium sized city at the moment(Stoke-on-Trent), and to the best of my belief there is only one folk club here, but there are loads of other outlets for folk music.The conclusion is inescapable: I am absolutely sure the folk clubs were the main purveyors of folk in say 1967, but they aren't in 2007.