Let us revisit what might prompt us to desire a state of self-sufficiency.
The idea of self-sufficient 'self-provisioning' -- in which a small group of people provide for all of their needs, using their own land -- is now, in most of the industrialized world, a fantasy.
One might imagine securing access to fertile land that comes along with a source of potable water. Gaining access to such land is increasingly difficult, but not impossible.
One might also start growing crops and raising animal sources of meat and dairy on that land. Perhaps even sufficient to feed a small group of people, or a family.
The soil inputs to a self-sufficient operation, however, would need to be sourced locally; even purchasing compost undermines true independence.
The feed for chickens and goats would similarly need to be produced on-site.
Further: where would necessary tools and technologies come from? Putting fossil fuel - powered technologies like tractors aside, how would even the simplest implements be produced? An effective hoe usually consists of a lightweight wooden pole with a specially shaped metal attachment at the end. Would the self-sufficient community be able to produce the handle, starting with a tree? Would the metal be sourced from local bog iron, and shaped using blacksmithing techniques?
For that matter -- basic heating might be done with wood; but if a wood stove were used, it would have to be made. And the wood for the heating would need to be sourced from local trees, adding to the land requirements for our 'self-sufficiency' picture.
Finally, any sort of modern communications devices -- phones, radios, computers of any sort -- are clearly impossible to produce locally, and cannot be considered a part of this 'self-provisioning' picture.
Note that if there is -- as there seems to be, in our analysis above -- a choice to be made between self-sufficiency and material comfort, wealth, food security, etc, then it seems that many people might choose the path of material comfort.
In fact, in recent decades our culture has, for various political and economic reasons, railed against the backwardness of the isolated self-provisioning community. It is not simply convenient to participate in the wider economy -- it is a moral imperative. Without full participation, the economy doesn't fully thrive; we all do more poorly when various groups opt out, substract their labor energies and their creativity.