A couple of years ago before Musk derailed completely, I was at a tradefair and listened to the keynote about entrepreneurship by some Silicon Valley guy whose name I forgot. He actually knew Musk in person and said that founding and developing businesses was like a game to him. According to him, he only cared about money in so far as it enables him to do what he loves. If he lost it, the primary concern would be that he couldn't start another venture, not that he would miss the luxury and comfort.
From that perspective, I think those characters are more about achievements than wealth. Trump didn't need to run for president to begin with, he only did so this time around because of the crimes he committed while in office. They're in pursue of power and legacy. And in that sense, it is also worth mentioning that personalities can change the longer you remain in an echochamber filled with yes sayers. I think that definitely happened to both of them, the same way it happened to Putin and affected his judgment. Humans don't fare well when their opinions aren't challenged and narcissistic character traits flourish under such circumstances.
And that's why I think that they will inevitably clash as well. By all accounts, Trump reacts pretty badly to people who tell him unpleasant truths and he doesn't like to share the limelight. Meanwhile, Musk will clash with Trump's erratic decision making and short term orientation. Two personalities like this won't get along forever, in my humble opinion.