A perspective on government, limited by function. What do you think of a hypothetical social contract, that limits the public sector, to providing public goods?
From this perspective a hypothetical state, could have a social contract that legally limits the economy to a duopoly of a public and a private sector.
The public sector could be legally bound to promote, and provide; for the general Welfare, of the populace of that state.
One metric of limiting the public sector by function, would be for that sector to administer public goods and services.
This form of division of labor could result in greater efficiencies (and from forms of cost reduction of the public sector) in the economy.