George Stigler attributes to Smith "the most important substantive proposition in all of economics" and foundation of resource-allocation theory. It is that, under competition, owners of resources (labor, land, and capital) will use them most profitably, resulting in an equal rate of return in equilibrium for all uses (adjusted for apparent differences arising from such factors as training, trust, hardship, and unemployment). He also describes Smith's theorem that "the division of labour is limited by the extent of the market" as the "core of a theory of the functions of firm and industry" and a "fundamental principle of economic organisation."
Paul Samuelson finds in Smith's pluralist use of supply and demand — as applied to wages, rents, and profit – a valid and valuable anticipation of the general equilibrium modelling of Walras a century later. Moreover, Smith's allowance for wage increases in the short and intermediate term from capital accumulation and invention added a realism missed later by Malthus, Ricardo, and Marx in their propounding a rigid subsistence-wage theory of labour supply.
In noting the last words of the Wealth of Nations,
- If any of the provinces of the British empire cannot be made to contribute towards the support of the whole empire, it is surely time that Great Britain should free herself from the expence of defending those provinces in time of war, and of supporting any part of their civil or military establishments in time of peace, and endeavour to accommodate her future views and designs to the real mediocrity of her circumstances.
Ronald Coase suggests that if Smith's earlier proposal of granting colonies representation in the British parliament proportional to their contributions to public revenues had been followed, "there would have been no 1776, ... America would now be ruling England, and we [in America] would be today celebrating Adam Smith not simply as the author of the Wealth of Nations, but hailing him as a founding father."
Mark Blaug argues that it was Smith's achievement to shift the burden of proof against those maintaining that the pursuit of self-interest does not achieve social good. But he notes Smith's relevant attention to definite institutional arrangements and process as disciplining self-interest to widen the scope of the market, accumulate capital, and grow income.
Libertarian theorist Murray Rothbard, however, disagrees, saying that Smith's influence has blinded economic historians to the writings and theories of economists prior to Smith. He also calls The Wealth of Nations "a huge, sprawling, inchoate, confused tome, rife with vagueness, ambiguity and deep inner contradictions."
Economic anthropologist David Graeber argues that throughout antiquity, one can identify many different systems of credit and later monetary exchange, drawing evidence for his argument from historical and also ethnographical records, that the traditional explanation for the origins of monetary economies from primitive bartering systems, as laid out by Adam Smith, doesn't find empirical support. The author argues that credit systems developed as means of account long before the advent of coinage around 600 BC, and can still be seen operating in non-monetary economies. The idea of barter, on the other hand, seems only to apply to limited exchanges between societies that had infrequent contact and often in a context of ritualized warfare, rendering its conceptualization among economists as a myth. As an alternative explanation for the creation of economic life, the author suggests that it originally related to social currencies, closely related to non-market quotidian interactions among a community and based on the "everyday communism" that is based on mutual expectations and responsibilities among individuals. This type of economy is, then, contrasted with the moral foundations of exchange based on formal equality and reciprocity (but not necessarily leading to market relations) and hierarchy, based on clear inequalities that tend to crystallize in customs and castes