it seems clear that there is some intermediate amount of goverment that supports the most eudaemonia

More nasty details: An amount of government which supports the most eudaemonia in the short term, may not be the best in the long term. For example, it could create a situation where the government can expand easily and has natural incentives to expand. Also, the specific amount of government may depend significantly on the technological level of society; inventions like internet or home-made pandemic viruses can change it.