A decentralized command economy is a contradiction in terms.Historically, yes, but you can't judge planned economies based on history alone. What about a de-centralized command economy done from the bottom up?
Precisely. You cannot have a free market without government regulation, just as you cannot have a fair game without a referee. When I say "free market" I do not mean a market free of regulation--quite the opposite, in fact.Governments do not uniformly reduce efficiency. Universal education increases efficiency, as do various other long term investments. Many regulations do more good than bad. Basic law and order is a prerequisite of a free market. And, redistributing wealth increases consumer demand by taking from the wealthy, who are good investors but poor consumers, and giving to the poor and middle class, who are poor investors but good consumers.