one comment called this the "anti Lord of the Flies".
Most survivalist stories are about the need for guns to survive and people just attacking each other. But in reality, if you want to survive the collapse of civilization, you need a community, and if there is not one, you need to build it yourself.
Yes, it's Heinlein.
The immigration problem, like the need for millions of Filipinos, Indians, Nepalese, Chinese, etc. to leave the children behind so parents can migrate to cities or overseas to support themselves and their families is one of the major problems of the modern economic system.