Most of those famous people don't manage their own accounts though. Some do, like Musk. That's why I'd consider stealing his DMs to be more dangerous than running a Bitcoin scam - it could easily upset Musk enough that he bugs the FBI to investigate seriously or, more likely, uses his own considerable resources to run an investigation. See how Bezos hired investigators when his data was leaked, and they did get to the bottom of it.

Trump is a bit of a special case because he's POTUS. I'm pretty sure there are no remotely interesting DMs on his account, but if there's one thing the US doesn't like, it's anyone even perceived of messing with national security. An attacker merely logging into Trump's account could be seen as a national security issue, and attract an entirely different level of law enforcement attention.