The idea that those relative prices can find a system-wide equilibrium is the heart of the neoclassical theory of value, a theory often called "Walrasian"
footnote 14
The Jevonian revolution definitively ended the hold of "who gets what," class-based analysis in orthodox economics, and instead consecrated the individual "consumer" as the unit of analysis.
In fact, the well-known neoclassical doctrine that "without interference" markets will function perfectly (or "clear") is also known as "demand theory".
The term "neoclassical" with respect to economics was coined in 1900 by the American economist Thorstein Veblen, the same person who first discussed "conspicuous consumption".
Smith was both extending and breaking with the analysis of the Physiocrats, political economists of eighteenth-century France who believed that the natural productivity of the land, set in motion by agriculture, was the origin of all wealth. For them, surplus value--the "additional" value produced between input and output in a production process--was possible only as a gift from nature. Their policy conclusion was logical if agriculture was the source of the surplus upon which the state and all society depended, then anything that hindered it (taxes, trade restrictions, etc.) was bad.
