Varoufakis wrote a blog post two years ago on the history of political economic thought on the firm. It also delves into Valve's unique management culture [1]. "There is one last bastion of economic activity that proved remarkably resistant to the triumph of the market: firms, companies and, later, corporations. Think about it: market-societies, or capitalism, are synonymous with firms, companies, corporations. And y…
Well, from what I understand, the hierarchy is basically entirely political / tribal. It clearly works for them, but let's not idealize it as a utopian dream without the typical petty human inter-office struggles.
When someone tells you there's no hierarchy in their company, there is, you're just not high up on it and no one's bothered writing the hierarchy down for a number of reasons - most commonly for Cool Startup Culture Points or because if the hierarchy was drawn out on paper it would scare the bejeezus out of anyone watching.
Unspoken or undefined hierarchies don't mean you don't have one, it just means there's a covert one that isn't subject to scrutiny or accountability.
Which isn't an endorsement for documenting every minutiae of rank and hierarchy, but rather an acknowledgment that hierarchy exists regardless of how badly you want it to not exist.