Mises on the nature of pure capitalism

From Money, Method, and the Market Process, Chapter 15, by Ludwig von Mises:

In a capitalist society the proprietary class is formed of people who have well succeeded in serving the needs of the consumers and of the heirs of such people. However, past merit and success give them only a temporary and continually contested advantage over other people. They are not only continually competing with one another, they have daily to defend their eminent position against newcomers aiming at their elimination. The operation of the market steadily removes incapable capitalists and entrepreneurs and replaces them by parvenus. It again and again makes poor men rich and rich men poor. The characteristic features of the proprietary class are that the composition of its membership is continually changing, that entrance into it is open to everybody, that continuance in membership requires an uninterrupted sequence of successful business operations, and that the membership is divided against itself by competition. The successful businessman is not interested in a policy of sheltering the unable capitalists and entrepreneurs against the vicissitudes of the market. Only the incompetent capitalists and entrepreneurs (mostly later generations) have a selfish interest in such "stabilizing" measures. However, within a world of pure capitalism, committed to the principles of a consumers' policy, they have no chance to secure such privileges.