That's not the world that Elon lives in. Elon in effect has infinite wealth. He could buy an island and still have infinite wealth. He could buy Twitter and burn it down and still have infinite wealth. He could make 100 other people billionaires and still have infinite wealth. There's no "instead" when it comes to talking about infinite wealth.
I think a more interesting question is why as a society do we allow people to have infinite wealth?
Because 'money' is just a denomination of share-of-control over the resources of the system that enforces it.
Therefore any person who has demonstrated their ability to deploy resources effectively (by whatever evaluative method used) 'earns' access to higher resource volumes to pursue their endeavors.
Get access to volumes above a certain level and your 'infinite wealth' criteria kick in.