I'm not convinced that this is borne out by history at all. Anyway, the argument against the effectiveness of autocracy is essentially the same as the argumen

I'm not convinced that this is borne out by history at all. Anyway, the argument against the effectiveness of autocracy is essentially the same as the argument of planned production vs markets for price discovery. The more you concentrate decision making on complex topics, the less the body making the decision has access to all the nuance and detail that are needed to make the correct decision. This usually gets even worse when the people bringing the (potentially upsetting) detail and nuance need also to maintain good relationships with the autocrat or face serious consequences. You saw this relationship between Trump and Fauci recently - if you're trying to say something that the person in charge doesn't like, then you are sidelined to the detriment of society. That's classic autocratic behaviour. But in this case the consequences for Fauci were constrained by the fact that it was happening in a mainly free society, and the society was able to correct itself after 4 years without having to murder a huge proportion of its population. The ability to do that is a massive benefit for a free society. There have been horrible famines killing many millions of people because the (smart, well-educated) person in charge thought they knew what was best. That is not efficient. Needing to build consensus is something that generally has to happen in a free society can slow you down, but it also exposes you to other views, and allows your mistakes and prejudices to be challenged. This allows you to make better, more effective decisions.