To compare, Walmart employs over 2M workers, and as efficient as they are, they still need to scale with the size of their business scope. Whether it's a linear scale or a log scale, they need more and more people as they do more and more.

The fact that the same order of magnitude number of people can administer an entire country as the number of people that it takes to administer a bunch of stores is actually remarkable.

The government has become more efficient over time and its size as a percentage of the population has reduced as the population has grown.

Government does have a constraint like that - it has to remain solvent. A government as powerful as the United States has many tricks it can use to do that, but at some point even it cannot do anything it wants.