I think you’re conflating the success of Meetup with the success of individual meetup groups. In the time the 20 groups you mentioned grew quiet and languished

I think you’re conflating the success of Meetup with the success of individual meetup groups. In the time the 20 groups you mentioned grew quiet and languished I’m sure Meetup signed up hundreds if not thousands of new meetup organizers. (It’s also ~$200 / year, not $300 / year, but now I’m just seeming pedantic.)