On monopolistic competition and optimal product diversity: workers ’ rents also matter

In the Dixit-Stiglitz model of monopolistic competition, entry of firms is socially too small. Other authors have shown that excess entry is also a possibility with other preferences for diversity. We show that workers' rents also contribute to explain excess entry through a general equilibrium mechanism. Larger wages indeed raises the aggregate earnings and firms sales and profits, which entices too many firms to enter. We discuss the possibility of over-provision of varieties by comparing the equilibrium to unconstrained and constrained social optima and to other regulatory framework where wages are not controlled.