Entry, Exit, Growth, and Innovation over the Product Life Cycle

摘要: Regularities concerning how entry, exit, market structure, and innovation vary from the birth of technologically progressive industries through maturity are summarized. A model emphasizing differences in firm innovative capabilities importance size appropriating returns is developed to explain regularities. The also explains regularities regarding relationship within between effort, productivity, cost, profitability. It predicts that over time firms devote more effort process but number rate diversity product eventually wither.