Matt Ridley offers a nice example of the problem in his book "The Rational Optimist":
In the same vein, Kelly Cobb of Drexel University set out to make a man's suit entirely from materials produced within 100 miles of her home. It took twenty artisans a total of 500 man-hours to achieve it and even then they had to get 8 percent of the materials from outside the 100-mile radius. If they worked for another year, they could get it all from within the limit, argued Cobb. To put it plainly, local sourcing multiplied the cost of a cheap suit roughly a hundred-fold.So local production is possible but only at a high price.