But.
Discord (not to mention Slack) will simply continue to be the lowest friction choice until a FOSS alternative comes along that is free to use, comes with rich moderation tools, supports fine-grained notification settings, supports offline history without additional effort, supports rich bots, has a mobile client that shares state with the desktop clients, and already exists on most people's desktops.
So to impact the open source communication landscape, the standard that needs to be exceeded is Slack and Discord, not IRC.