there’s no persistence or community.
That's it right there, that's what you are missing. The older forum communities were small enough that you could keep track of whose who, something that isn't possible when the user counts are in the tens of thousands to tens of millions. I think a lot of us olds would like to go back to that but its impossible; our monkey brains can't handle communities of that size.
XenoForo is a bit spendy but they're providing the software, hosting and data storage. IIRC the forum I'm talking about is on the "Business" plan due to how busy it is.