It must be emphasized, because the contrary has so often been asserted, that Marx was not trying to reduce everything to economic terms. He was rathe… - Paul Sweezy

Capitalist society is characterized by a degree of labor mobility much greater than prevailed in any previous form of society.

Supply and demand will be in equilibrium only when the price of every commodity is proportional to the labor time required to produce it. Conversely prices proportional to labor times will be established only if the forces of competitive supply and demand are allowed to work themselves out freely. The competitive supply-and-demand theory of price determination is hence not only not inconsistent with the labor theory; rather it forms an integral, if sometimes unrecognized, part of the labor theory.

The legitimate purpose of abstraction in social science is never to get away from the real world but rather to isolate certain aspects of the real world for intensive investigation.