I have looked into those and Mumble is pure voice and no video or screen sharing and specifically doesn't want to do this for the past 5 years

Jitsi meet does not have drop-in, dropout ventrillo style channels and has Skype style calls (my info could be out of date).

IRC having those features isn't available yet and who knows when it will happen.

So it seems to me that there was still no alternative when most people on discord were looking for a group chat/voice/video app.

Don't get me wrong, I used vent, Mumble, xfire, etc.. Back in the day. But it is disingenuous from the original commenter to say that people just traded the same features for a closed system. Fuck discord though.

Matrix is also getting there.