Because all the evidence shows...
What evidence shows that? This post is in fediverse@lemmy.world and crossposted to fediverse@lemmy.ml. There's also fediverse@kbin.social and I know I've seen others. Most of these communities have been running for a few years now and there's still no consolidation.
You can see the same pattern with communities for gaming, linux, gardening, movies, tv, etc. I'm subscribed to multiple communities for each of those topics on separate servers because the consolidation doesn't happen.