You've got to step back a little to understand.

The key thing is that it is not possible (excluding inheritance) to become a billionaire without being a scheming psychopathic cut-throat selfish person and having a determined drive to have power over others.

The second key is it's not possible to keep your billions without being a psychopath. This because you could never possibly spend that money in your lifetime and the only way to have accumulated it is through exploitation of labour.

So it's a thing you don't need that you got via abusing others. They want power and they don't care how they get it. They have no plan beyond that. Personally I think it's mental health issues and the fact that we allow this in our flawed system.