People have mentioned the need for a facebook alternative on the #fediverse, but now I'm wondering if that's true.

If you have microblogging (#mastodon, #pleroma), macroblogging (#plume), and event management (#gettogether) all federated and talking to each other, you don't really need a one-stop solution. There's no reason you couldn't have a platform that does it all, but for the small teams that are building these projects, maybe it makes sense to limit the focus of the project and rely on federation and other projects to fill in gaps.