Piketty’s argument was not just that income inequality would increase, but that it would increase because the return on capital is greater than the growth rate of the economy, so, in his words, "It is almost inevitable that inherited wealth will dominate wealth amassed from a lifetime's labor by a wide margin".

But inherited wealth does not dominate wealth amassed from a lifetime's labor. The largest fortunes today are dominated by people who built businesses, not by people who inherited their wealth. So if "there are fewer than 1,000 billionaires and the vast majority of them are self-made", that is a direct refutation of Pikkety's thesis.

It is hard to overstate just how bad Pikkety's arguments are. His argument assumes single inheritance of fortunes, it assumes that wealthy people don't donate significant sums to charity, it assumes that inheritors of wealth will invest that wealth as wisely as the person who created it, along with many, many other false assumptions. The most egregious one in my opinion is that it assumes the wealthy don't spend their money.

If a billionaire makes a 5% return on his billion dollars and spends $50 million dollars a year, does wealth inequality increase? No, it does not.

It's a ridiculous theory, it is directly contradicted by the facts, and I have no idea why it is taken seriously by people here other than just as an opportunity to participate in a 2 minutes hate against rich people.

They're saying that self-made billionaires didn't inherit their wealth. Which means they created it. Which means that it created useful economic activity. And since rich people dont optimally pass on their wealth, those 1000 billionaires' spawn are likely to piss away that wealth while 1000 more economically active individuals create more healthy economic activity in pursuit of becoming billionaires so that they can pass on their wealth to their children to piss away, ad. Inf.