No I don't think charging joining fees would work.
I've been a member for a few years now, I post occasionally and join in some discussions but sometimes I just have a nose through too see if there's any news,
maybe events advertised.
I have helped a few new arrivals with items no longer needed or advise helping people settling in, I have also made some lovely fiends along the way.
Charging will put people off joining as number would fall.