@ Kenny
I can't make a comparison between numbers attending on a typical night now and twenty years ago as my experience only spans three years.
A typical night at my club has around 20 people attending. I've seen numbers reaching almost thirty.
From my own observations, as a relative newcomer, thriving isn't just about numbers attending. For me, It's also about inclusivity,diversity of players/singers, range of abilities, feeling safe to try something out and make mistakes without judgement, having a laugh, sharing ideas,sometimes instruments, a warm welcome for newcomers ( and there have been several while I have been attending,)masses of sandwiches served on the night( including cheese and onion!) good ales (although I'm a lager drinker, I'm afraid),regular concert nights, special folk events involving loads more ale and more sandwiches.
The regular folk nights sees regulars attending that neither play nor sing, but just like to listen to the music, as does the landlady.
This is my own definition of 'thriving'and it keeps me coming back week after week, work willing.