I don’t think the socialists could take that line as effectively. After all sometimes business earns profit and sometimes it suffers losses. Karl Marx was trained as a classical economists and argued more tellingly from a general equilibrium position in which there are neither entrepreneurial profits nor losses. How then, could a classical economist who had no time preference theory of interest, explain the normal rate of return to investment?
You might try reading Boehm-Bawerk’s book to get an historical perspective: