Capitalism

According to a recent feature on National Public Radio, a T-shirt, for which you may pay as much as $20 here in the U.S., costs about $2 to make. $1.50 of that cost to the manufacturer is materials (fabric, thread, machines). $0.50 is labor cost. 

The $18 over the cost goes to various people in the supply chain which gets the T-shirt from Bangladesh to you. The shippers, the distributors, the retailers. The cotton in the T-shirt may have come from Mississippi (by some measures the poorest state in the U.S.) and has traveled the globe on its way to your local Walmart. 

Is capitalism efficient? Is capitalism effective at distributing wealth fairly? Does capitalism have any investment in local communities beyond profits? Why then are so many governments and individuals touting the popular myth that free-market capitalism is the best economic system?