Well, but those factories exist in a system that is administrated by humans. Humans are involved everywhere, and that leads to inefficiency.
There's an assumption there that systems where humans aren't involved are more efficient. But it's not the absence of humans that is the solution. It's the presence of an automated system, which is always invented by humans.
Of course it is.
But, considering that we as humans aren't wired correctly to take care of the needs of an entire society (in fact, Humans in general have trouble caring about more than their immediate social circle, which is usually in the 100- to 150 people range), which is why a system that is actively administrated by humans cannot be guaranteed to be as efficient as an algorithmically controlled one. Which also means that, once you switch on your turnkey economy,
you have to leave it alone. Once humans get involved in the decision-making, you will get inefficiency.