The theory within the industry is a critique of the traditional theory, especially the assumptions are more in line with reality. If the interests of the industry can exist for a long time, this actually shows that the market of free competition does not exist, because the free entry of other manufacturers into this industry with interests will be restricted, so it does not belong to the market of perfect competition, but the market of imperfect competition.
In addition, the theory not only discusses from the supply side, but also examines it from the perspective of demand, which actually transforms the implicit assumption that the best interest equals the national interest in Ricardo's theory into a benefit for both the supplier and the demander. This theory also believes that economies of scale are an important part of the contemporary economy, and it is the interests that all countries are pursuing, and the interests of economies of scale are regarded as the interests of the industry, and this analysis is closer to reality.
The theory of intra-industry is a supplement to the theory of comparative interest, which reveals that Ricardo's theory of comparative interest and the traditional He-Russian model are used to explain the rationality of primary products and standardized products, but the reasons for the occurrence of intra-industry should be explained from other perspectives. The theory of intra-industry ** is still a static analysis, but in terms of policy recommendations, the theory agrees with dynamic recommendations.