My prediction is he ends up growing twitter into a fairly bland chat/communications app/social network, and the focus on global political and social debates slowly weans over time.
So far Musk's brought back a very high profile antisemite (Ye) and a bunch of others took the hint to return to Twitter. I'm pretty sure bland isn't the right word.
https://www.sfgate.com/business/article/Racist-tweets-quickl...
"Elon now controls twitter. Unleash the racial slurs. K---S AND N-----S," said
one account, using slurs for Jews and Black people. "I can freely express how
much I hate n-----s . . . now, thank you elon," another said.
…
Some of the Twitter influx was organized on other platforms, including the pro-Trump
forum TheDonald, where its top posts Friday morning showed tweets celebrating lies
about Trump's 2020 election loss and memes criticizing transgender people under the
headline "When you can't get banned on Twitter anymore."
My prediction is Musk flails about, burns a pile of money, and decimates any goodwill his associated companies (e.g. SpaceX, Tesla, Starlink) currently have.