Every increase in transportation costs makes local farming and manufacturing that much more attractive.
Victory Gardens
Neighborhood Co-ops
True but it may still not be profitable or even more fuel efficient than large scale farming and bulk shipping. This is due to the economies of scale.
I live in a farming district and I am familiar with farming history. 175 years ago each local farmer grew a little bit of everything. Take wheat for instance. Each farmer would grow a small amount of wheat and transport it to a grain mill in his town. Lots of small wheat fields and lots of small local grain mills. Lots of wagons to transport the grain to the mill and flour from the mill to the local stores.
When better farming equipment and railroads were introduced the cost of flour dropped dramatically. Farming became more specialized and cost efficient. It was simply not profitable to grow wheat on every small family farm. This trend has continued ever since.
Transporting grain or flour via rail is very fuel efficient, even over long distance. Probably more fuel efficient than having thousands of small local trucks doing the same thing over very short distances.
The other thing I don't understand about the buy local concept is variety. What kind of locally grown green vegetables would be available after the frost? What kind of locally grown citrus fruit would be available any time of year in northern climates?