sentences:  This traces to Austrian-American political scientist Joseph Schumpeter's notion that a "perennial gale of creative destruction" is ever sweeping through capitalist economies, driving enterprise at the market's mercy.Contrasting with the allocatively, productively and dynamically efficient market model are monopolies, oligopolies, and cartels.When only one or a few firms exist in the market, and there is no credible threat of the entry of competing firms, prices raise above the competitive level, to either a monopolistic or oligopolistic equilibrium price.