Although I understand the argument for growing things where it is cheapest...and then shipping them all over the earth, it seems more sensible to distribute food production as much as possible. One, it lessens the possibility of a pest or virus wiping out all the crops that are concentrated in a particular region. Two, according to some medicinal thought, locally grown food is healthier. Three, shipping food all over the world means the food won't be as fresh. Four, shipping food all over the world means the cost/work/expense/pollution of shipping. Five, looking at fields under cultivation is very comforting. Six, there would be greater occasion for experimentation in cultivation if this were spread out over many cultures. In sum, I don't ultimately see the "efficiency" argument.
We all know that we have the means (at this stage in history) to support the livelihood of farmers, where ever they may be. It is only in the magical "free" realm of capitalism that the farmer has to starve. Fuck the market. It's no substitute for intelligence.
Joanna