There was a time when everyone was a locavore. The milkman delivered fresh local milk from the dairy just outside town. Prime cuts of meat could be selected from the butcher shop downtown, which purchased its stock from the rancher in the next county. Vegetables grown at the local farm were available at the market.
Then, as the industrial revolution took hold, everything began to change. The practices that revolutionized the manufacturing world started to find application in the world of agriculture. Synthetic fertilizers were developed. The chemical arms race of WWII resulted in the creation of synthetic pesticides.