Until video conferencing greatly improves, voice channels with push-to-talk are a thing, bot management more streamlined, giphy / tenor integration, proper roles / permission system added, server customizable sidepanel for organization, etc. is implemented I don't see it supplanting Discord.

I say this as someone that leads an open source org with a Matrix Space. Discord may be proprietary but it's objectively better in many ways, so it should not surprise people that Discord is picked