Maybe. Or maybe he's just saying that to make money. If Elon Musk ends up being completely successful in all of his endeavors, he will be the world's richest person by far.
I suspect the truth is in the middle. He does want to change the world, but he's not willing to become poor (let's say a net worth of less than a million dollars) in the process.
I have no problem with people getting rich, especially if they've earned it. But I see Elon Musk as a salesman more than anything, and he's damn good at it. He has generated a cult following of people who believe he is doing everything possible to save the planet.
I am very skeptical that Elon Musk is half as great as he's made out to be on certain internet forums. I do not mean to say he is not an incredibly accomplished person, only to say that he does not live up to his self-generated hype.
Of course time will tell. I truly hope he is as great as people make him out to be. But I just don't see it. Hopefully he makes me into a believer by delivering on all his promises.