I'd guess that a huge of the reason is insurance, regulation and safety laws. Getting a fully automated "dark" factory would require lots of money and skill.

I'd guess that a huge of the reason is insurance, regulation and safety laws. Getting a fully automated "dark" factory would require lots of money and skill. Any company that can afford that level of automation is going to operate in a country with various fire codes and insurance requirements that probably out cost the benefit of having zero human oversight. If the humans must be around they might as well work, no reason to invest $50mil automating something the people that have to be there can do. If there are dark factories they are in a place where the authorities don't care if it burns down at night and takes half the business/slum district with it.