You’re exaggerating, I can definitely see how Twitter users changed the general atmosphere of the Fediverse, at least on the instances that I have used in the past. As for Reddit, I think it will be something similar to that, not everyone is going to migrate but Lemmy is going to be significantly bigger, better and THE place to go if you want to ditch Reddit. Also, it’s not like having a big portion here of social media audience is going to do a lot of good. I have serious doubts about people being able to give value to the community if they can’t even figure out how to register on an instance other than the main one