Fediverse is one possibe technology that can be used to implement this, but the core problem is not a technological one. Even in the Fediverse instances will refuse to peer with other instances - something that I don't think should be allowed for massive social networks that use their network effects to capture users.

i mean forcing the dominant networks to interoperate with the fediverse. i can open as many diaspora and mastodon accounts as i want, i will still be alone because everyone i know is on twitter and facebook. make it mandatory that facebook and twitter lets me connect my fediverse accounts and i can connect with my friends regardless of their network of choice