But that's not really identity then right? That just becomes my hnews/reddit username that's unverified.

I read @elonmusk because I trust it's him and I'm interested in what he says. Personally, I genuinely like Starship + Starlink updates... I ignore most the other stuff. But still, I want to see those awesome rocket tweets!

So, I want to know what he says.

He can change his username because it got hacked/whatever... but then I personally have to see what he changed it to... how do I know that he is the one who changed it? how do i know it's not some rando dude impersonating him?