Krugman et al. 2022

Krugman P., Obstfeld M., Melitz M. 2022. International Economics: Theory and Policy* (12th ed, Pearson Education, United Kingdom).

Krugman et al. argue that in general the policy of free trade surpasses all other governmental strategies, including for smaller nations that don't have influence over international export prices. They and other economists suggest that smaller or developing countries can reap gains from free trade beyond what traditional cost-benefit analyses capture. One such benefit is utilisation of economies of scale, where the cost per unit decreases as the industry's size expands, not just the size of individual businesses. Free trade enables smaller countries to focus on specific industries, allowing them to boost efficiency through large-scale production, which in turn can reduce costs and enhance profits. In contrast, protectionist policies can restrict these benefits by discouraging industry concentration.(p. 278)