I mean, it DOES happen. A few of us in our area garden, have chickens, bees or make baked goods. We typically plan out what everyone is going to produce and how much we need and share. You’d be surprised how much you can grow on a relatively small plot. We used to be in the might of town on a standard plat, and had about 1000 square feet of vegetable garden, bee hives, half dozen chickens and a bunch of fruit trees. We produced about 80% of the produce for our family of 7. Now we’re in the country and have doubled those numbers, plus added goats and pigs. There is a substantial set up cost, and it’s hard to do as a renter, but definitely possible.