Why Some Jobs Pay More Than Others — The Wealth of Nations

Smith asks why pay differs if competition should equalise advantages within a neighbourhood. In perfect liberty, people would crowd into the best-paid trades until returns matched again. They do not, because employments differ in hardship, dignity, training, trust, steadiness, and probability of success. The butcher's trade is brutal and coarse, yet often pays better than many respectable crafts because fewer people will endure it. Easy, honourable work can pay less because more candidates accept it. Smith's first lesson is that money rewards are not a clean measure of skill alone; they compensate what the worker gives up to do the job. Equal money wages often buy more in the country than in town because provisions are cheaper, so real advantage must be judged by what pay commands, not the headline figure alone.