Personally I’m finding it difficult to believe a billionaire can go broke due to the worse state of an economy. When I mean broke. To the extend of selling off properties and barely afford a living.
I agree with you. Hardly ever a billionaire is going to complete bankruptcy, because he has just too money to burn by there. It can take a long time to build an empire, but an empire also doesn't go to complete ruin at once.
On other hand yes I guess its hard for them to be in that situation since most of them their money is not stored on their local currency. Majority of them either they hide their wealth on Gold,USD and other assets which cannot easy get affected by inflation or crisis happening in their country.
They are Billionaire because they know how to handle their money and for sure they have good financial advisors that give certain good advice on what to do especially if there's serious happening in their country. Also its really hard to ruin their empire especially if they are already establish person or institution.