"How old are you? Lots of folk clubs back in the heyday had attendances of 100, and even then, they were turning people away. "

Im the late 60s / early 70s went to clubs where, if you went to the bar, you had to wait for somebody else to want a drink before you could get back in. I also went to clubs (seldom more than once) with only a handful of people and most often to clubs that were comfortable busy. From venue sizes where I lived I would have put a typical audience in the 40 - 50 mark.