But (Picketty continues), oligarchy is intrinsically destabilizing. For one thing, once the fortunes of Bill Gates' or Liliane Bettencourt's are large enough, growing them by even, say 1% requires that some capital come from other rich people, because 1% of Bill Gates's holdings will eventually exceed 100% of the holdings of everyone who isn't insanely right. So, over time, rich people eventually have to fight with each other in order to keep getting richer - see, e.g., WWI.
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