The provision of convenience and variety by the market
研究了消费者面临购买成本（如旅行或等待时间）时，这些成本如何影响市场对多样性的需求和供给，以及便利性竞争对市场集中度的影响。
Consumers commonly face purchasing costs, for example, travel or wait time, that are fixed to quantity but increase with variety. This article investigates the impact of such costs on the demand and supply of variety. Purchasing costs limit demand for variety like prices limit demand for quantity. When demand for variety is low, manufacturers generally invest substantially in lowering purchasing costs, to attract consumers. In the monopolistic competition free‐entry equilibrium, providing convenience increases the demand for variety, but its costs reduce supply. The desirability of nonprice competition in convenience and its implications for variety and market concentration are discussed.