If you take a close look at communal living around the world you will notice that there are very few well run communes that are (much) larger than about 100 people, and many of the most successful communes split into two when the commune becomes too large. The reason for this is that as a commune grows larger corruption and favouritism become larger and larger problems, and when the leadership of a commune is no longer accountable to every member of the community it tends to fail.
The same pattern is demonstrated in modern governments being that the governments of most small towns tend to be run very efficiently, with little waste or favouritism while larger cities, state and federal governments around the world tend to see increasing levels of favouritism and corruption everywhere. When you’re dealing with a federal government that represents (roughly) 300 Million people and is already spending more per capita on government run insurance (Medicare and Medicaid) while covering a fraction of the people of smaller countries, why would you assume that a greater role of this government in healthcare would reduce costs?
