Depending just on agri land was what people a few hundred years ago. You want to go back and the difficulties that people face, try for a year to use just the agri land and nothing else.
See how much problem you will face. Agri is important and sustains food for life, but the advances in science and technology have made the world easier and smaller. Science has contributed enough back to agri.
You don't have to think of always eating including NUTS AND BOLTS.
