I would disagree, there's probably about 100 with some overlap, the sites the gikopoi weirdo owns, the pissu people and their IRCs. There's also the discords, which most imageboards and forums just seem to be anchors for these days.

I doubt there's many old school jpsies left hanging around BBSes, honestly, even in the heyday they had a shorter lifespan than most anons, if you follow one around on an archive they typically only lasted around two years.

It's weird to think we're in the twilight of the whole imageboard thing, I wonder if they'll be a novelty for graybeards in the future like actual BBSes are nowadays.