Selection bias is the elephant in the room. People who attend meetups are self-selected as more committed and social than average users

That's all that is.

btw: I think I was at the very first meetup, ever.
It was in Hamburg, organized by sirtoniwinchester (remember that guy? can't find the correct spelling rn). Met @pharesim there.
However, I was there to learn about the tech. Later meetups were less and less techy.