It's possible that various Discord servers, or obscure streamer chatrooms still feel like this, and we're just old. But it definitely feels like the default has become very top-down and public instead of bottom-up and intimate.
I think the difference there is streamers are just there to get money from their audiences. Doing something they like sure, but a vast majority are trying to make a living. That has a different context entirely.
I think there's an extremely long tail of streamers and associated chat communities that are untroubled by any form of financial rewards. When I speak to people in those communities it sounds to me like the closest thing to IRC in the 90s - tight-knit groups with regular comings together at specific times and places, being their whole selves with each other.