To relegate the environment of evolutionary adaptation to some small group with strange beliefs is to discount human nature.
Urbanization is a very recent phenomenon, and although it has driven most of recent human genetic evolution, it is hardly fair to call this "human nature" just yet.
Indeed, recall that my premise of "natural law" had a nuclear family with a head of household living as an individual sovereign on his own land with his own tools/weapons. "A man's home is his castle." "Every man a king." These are not just sales pitches if we take individual sovereignty and human nature seriously. Think about the population structure of the people founding the US.
The clear outcome of this contract between Americans would be a massive exodus from the cities back to "God, country and the good life" -- as a lifestyle preference, not a professional preference. As to advanced medical care, death is not a "disease" that can be "cured". It is build into our very nature as a sexually reproducing species. What we can expect to happen is that by getting the government out of anything to do with medical care, there would be a wide variety of choices available at much lower cost.
If you read nothing else, read this: A Contract Between Americans