Evidence is in mathematics. Central control is always more efficient, because control overhead is constant everywhere but the central node, where it grows linearly, whereas in fully distributed system overhead grows exponentially at each node. That's why anywhere you have more than a dozen of humans or even computer systems talking together, a hierarchy develops. Note that even companies fiercely competing on the market are internally run top down. And "vertical integration", so hot a topic in business nowadays, is essentially a code word for "centrally planned economy".

Distributed systems have many interesting properties, like resilience / fault-tolerance and flexibility. But efficiency is not one of those properties, as evidenced by ridiculous amount of waste generated by the process of competition.

Note that I'm not arguing the soviets were right and the world should be run from Moscow. I do however believe that spectacular failure modes of centrally planned economies were caused mostly by slow, incomplete and unreliable feedback loops, and not because the idea is inherently bad (it works for businesses pretty well). Moreover, I hate this clueless criticizing I frequently see that "centralized = bad", "distributed = good". Truth is, "distributed = wasteful", "centralized = efficient", but sometimes it's worth to be inefficient to get the benefits distribution brings.