> Bill Gates is giving away the vast majority of his wealth

That's a tax-avoidance scheme. Here's a recent (and certainly not the first) article laying it out:

https://www.inc.com/geoffrey-james/bill-gates-promised-to-gi...

> You don't know what Elon Musk will do with his wealth

I think we both know that whatever it is, first and foremost it'll be good for Elon Musk.