While Matrix clearly is the superb system and I would absolutely love to see people to migrate to it, but I have a feeling that people will use the solution that comes the closest to what they are used to - which is revolt at this point.
But revolt,imho, is not quite there yet and would very likely collapse under the increasing pressure on their ressources, just like many Lemmy or Mastodon servers did back in the day - but revolt is far less decentralized.
Which would send people straight back to Discord.
A shame,really, Matrix is clearly the better system,but VoIP/Video/Community building is not quite there yet.
It might be with Element X,but we will see.
Maybe I am wrong and I would love to be wrong here - I actually operate a small Matrix server and it's a fantastic system.