That's why commercial services just work. If I want to provide best-effort support for some library of mine I can set up a Gitter channel or a Discord "server"

That's why commercial services just work. If I want to provide best-effort support for some library of mine I can set up a Gitter channel or a Discord "server" and it will work for sync and async communication, with incredibly low barrier for participation to boot. I could set up a clever bouncer for my own account, but anyone who asks a question when everyone else is asleep and logs off will never learn the answer. Yes, that's what async communication services are for, I know. I could run a bulletin board, or use GitHub discussions or Discourse, but the ship has sailed: people are used to chats full of features.