We have long-form articles for blogging, already, and they are designed to be versioned.
Microblogging is meant for a different purpose. It's meant to be an uncensorable method for a human to express themselves.
Making it editable will encourage people to pressure others to change the content and make readers more wary about whether the visible author actually wrote the note or uncertain if they're looking at the correct one (as you described).
Or eventually allow people to write directly into the note, (through a reaction function, rather than a signature, like with community notes) so that, if you scroll their profile timeline, you see what is effectively graffiti or messages like "This is misinformation. For accurate reporting, please go to whitehouse.gov."
It's a cultural change, not just a technical one. He's recreating Twitter and co., rather than staying weird.