I was thinking of something smaller-- I don't see people talking about a social group or organization which was both diverse and safe (or perhaps even just reliably safe for non-privileged people), even if it was just for a short but extraordinary period.

Uh.

This might be an outside context problem.

I see people talk about that plenty -- I've been within groups and organizations that tried, in varying ways and with varying success, to realize that idea. They're usually support groups or nonprofit organizations that provide services to marginalized populations, and the idea of broadly-safe space as a core goal is built right in.

Yes, I remember when as a teen I first read Diane Duane's "Door into..." series and found it a beautiful idea, but completely implausible, that a woman could have a wife. And yet it happened. And it isn't a tenth of the way to what a world would be like without patriarchy.

Let me put it this way - I think that the endpoint would be a culture that doesn't even socially mark sex as a category, treating it as (in any given pair of a mated group) "biologically compatible as-is" or "biologically compatible with medical help" (such as stem cell gametes, in-vitro organ-printed wombs, etc) that latter encompassing both homogamete and infertile pairs, that does mark gender identity but doesn't assume there are only two nor does it correlate them with gametes, and in which clothing style, or femme versus butch, doesn't correlate either with either gametes or gender identity.