And with Elon's competitive personality you know he wants to surpass Bezos as the richest man in the world.
Elon passed Bezos a while ago. Elon is already the world's "richest". There may be others with more money but they are not publicly listed. 
https://www.forbes.com/real-time-billionaires/#415d76ab3d78
Elon: $315.7 billion
Jeff: $218.8 billion