This was my thought as well. Before learning more about the fediverse, I thought things are distributed and are replicated across servers (much like how distributed storage and computing works). But apparently they're not. You still have to choose which instance you want to use as your "home", and your data and your contents stays in your home. Others get to look at your profile and contents thanks to ActivityPub.
I understand the needs for multiple instances (i.e., preferences for moderating concents, governance, etc.) But shouldn't the users and the user generated contents (arguably fediverse's valuable resources) should be safe-guarded by having redundancies in place across multiple instances?
Has there any work or effort on this?
This kind of describes what's actually happened.