Purpose: This paper aims to discuss whether product research and development (R&D) in developed economies tends to be too high compared with the socially desired level. Design/methodology/approach: In this context, a model of vertical and horizontal product differentiation within the Dixit-Stiglitz framework of monopolistic competition is set up. Firms compete in horizontal attributes of their products, and also in quality that can be controlled by R&D investments. Findings: The paper reveals that in monopolistic-competitive industries, R&D intensity is positively correlated with market concentration. Furthermore, welfare and policy analysis demonstrate an overinvestment in R&D with the result that vertical differentiation is too high and horizontal differentiation is too low. The only effective policy instrument in order to contain welfare losses is a price control of R&D services. Originality/value: Considering the extent of product R&D as well as the political efforts to promote public and private research, this paper scrutinizes its benefit incorporating income and employment effects. Thus, it goes beyond partial-analytical models of the existing industrial organization literature and provides a larger base of political analysis. © Emerald Group Publishing Limited.