Mastodon feels like a step in the right direction, waayyyy too late..
Semi-decentralised (self-hosted servers) should've been the 2000's era, technology permitting.
But it wasn't.
I think it's what Tim Berners-Lee originally envisioned for around that timeframe, but centralisation won.
I think Nostr is outright skipping the "logical next step from centralisation" to full decentralisation because technology reached an inflection point that permits it.
But yeh, I shut my server down a few weeks after spinning it up and using it everyday... A lot of stuff was just missing (especially the ⚡ zaps⚡) or questionably designed.