Cool people use ActivityPub. Single vendor owned & controlled standards always turn out badly, just a question when.
Really basically: Everyone can have their data (posts, media attachments) on whatever server they want or control, easily self hosted.
And at the same time, people can also host "apps" like Bluesky that read said data and interpret conventions in naming to show it in a meaningfull way like as posts.
you can self host your data.
you can self host a bluesky view.
It actually kind of reminds me of openstreetmap, where it's actually only a database of keys and values, but apps interpret their meanings based on conventions