There is such thing as current relative advantage; and to change what your relative advantage is, it may be useful to restrict some of the trade.<p>Also, having ten inefficient suppliers is often better than having one very efficient monopoly — because it is usually also efficient at overcharging.<p>If the incentives are perfectly aligned and there is a medium term success or failure to consider, relative advantage works as advertised; but this will be closer to three equal startup co-founders dividing the work in the early stages than to international trade.