1. Yeh - but what sets Matrix aside is that you're abstracted away from the conceptual side of federation. As I said, this is about UI as much as anything else. Non nerds are used to "going to InstaFaceTubeDdit and seeing the stuff they want to read" - not having to wrangle with the conceptual stuff about instances, weird looking addresses and usernames, etc.

2. I mean, Wikipedia, but it's not the point. Yes, us tech people are maybe concerned about things being shit, lock-in, etc - but literally no-one else cares. So our best approach isn't to make something perfect from the tech point of view, but perfect enough that there is mass migration to it - because, as we all know, it ain't about the tech, it's about the momentum, content and growth. And in order to get these into a serious shape, we need migration. And to get migration we need slick, beautiful, easy to use UIs.