Why does Ruby still have this artisinal aura to it, never seen C/C++ For Good gathering.
I think it's the community. As an outsider watching a friend who is deeply involved with the Ruby ecosystem, I am in awe of the support they get even for small, artisanal-seeming projects from other devs in the community. I've seen them become a better a developer simply by showing up to conferences, talking to other maintainers and participating in the community.
I would not know, but I also do not think that an event xyz in one place at time, reflects all of a community either. So I could not tell you what the people there do; probably they want to socialize. I think creating and maintaining high quality project would be much more important but maybe that's just me. All the main drivers in ruby, have been written ages ago really - rails, _why the lucky stiff, even the old "Learn to program" tutorial from Chris Pine and so forth. That is not to say that no innovation has happened since then, of course, but it seems the peak days are really far, far behind now ...
Ruby is still a great programming language, but it really needs to intensify the effort to get out of the pit-of-decline.
I can't answer for others, but IMO, Ruby is the most elegant and expressive general purpose programming language that has reached a significant level of maturity and large audience.
If you write Ruby for a few years, and then you "go back" to other languages, you will groan. That's not to say that some other languages do not have things that we wish Ruby had, but often those other things would not really fit well with Ruby.
Nothing is perfect from every angle. But writing Ruby can be a joy for some of us.