In practice, any distributed system that doesn't have an explicit hierarchy evolves to have an implicit hierarchy, because economies of scale and network effects favor the increasing concentration of resources and connectivity, respectively. The OP is right about that.

In any distributed system, those nodes that by luck or skill become more cost-efficient and inter-connected tend to become even more cost-efficient and inter-connected, because all other nodes want to connect via the most cost-efficient, most inter-connected nodes.

This dynamic is self-reinforcing. We are all familiar with it.

Without some form of regulation (historically centralized, and always imperfect), distributed systems like market-driven economies, modern financial markets, and information networks evolve to have growing inequality of resources and connectivity over time.

I'm not aware of any exception.