I look at the following points in Schumpter’s book.
The possibility and maybe inevitability of socialism
Socialism depends on a mixture if economic stasis and concessions to market mechanisms to work.
Capitalism as better than its predecessors, or any possible socialist society, for delivering improving living standards for everyone including the poorest.
Capitalisms rests on the individual initiative of entrepreneurs, which is important in economic theory. It is also important for liberty, in a culture of individual rights and respect for law.
The tendency of capitalism to create its own opponents in a disaffected intelligentsia and to protect their rights, and even to elevate them to high cultural status.
The tendency of capitalism to create big businesses and share holders who are detached from day to day economic profits and losses, and tend to lose the entrepreneurial spirit.
Socialism cannot work as intended by its most idealistic supports, partly because of he inevitability of at least some inequality and some price mechanism; and partly because of the impossibility of forming a pure will of the people.
The problems of forming a pure will exist in democracy in general, as there are always different interests and factions within the People, and different ways of constructing that will. In general democracy becomes a way in which electors seek economic advantage and political groups try to get majority support through offering such advantages.
Schumpeter offers a paradoxical classic of liberalism, in showing the strength of anti-liberal tendencies in liberal capitalist society. It’s a classic of liberal thought in showing the decline of freedom and economic dynamism involved, so showing what needs to be resisted.