I don't think folk clubs are dominated by the middle class.

When my late wife Jacqui, our son's young friend Royston (who would then have been in his early 20s), and I formed Roger the Chorister (there was a fourth founder member but he left almost immediately) several of the stalwarts at the then Rainham Oast club dubbed us "the Shinyarses" because we all had desk jobs which was the exception rather than the rule. I guess that would have been about 15 years ago but I don't see much change.