“The capitalist system of production, once it had given all it was capable of giving, became an abysmal obstacle to the progress of humanity.”

The consumers are the sovereign people. The capitalists, the entrepreneurs, and the farmers are the people’s mandatories. If they do not obey, if they fail to produce, at the lowest possible cost, what the consumers are asking for, they lose their office. Their task is service to the consumer. Profit and loss are the instruments by means of which the consumers keep a tight rein on all business activities.
Source: Bureaucracy (1944), Chapter I: Profit Management, § 1: The Operation of The Market Mechanism

Introduction to Capital. Introduction to volume 1 (1976)

Anarchism: Its Philosophy and Ideal (1896)
Context: The masses have never believed in sophisms taught by economists, uttered more to confirm exploiters in their rights than to convert exploited! Peasants and workers, crushed by misery and finding no support in the well-to-do classes, have let things go, save from time to time when they have affirmed their rights by insurrection. And if workers ever thought that the day would come when personal appropriation of capital would profit all by turning it into a stock of wealth to be shared by all, this illusion is vanishing like so many others. The worker perceives that he has been disinherited, and that disinherited he will remain, unless he has recourse to strikes or revolts to tear from his masters the smallest part of riches built up by his own efforts; that is to say, in order to get that little, he already must impose on himself the pangs of hunger and face imprisonment, if not exposure to Imperial, Royal, or Republican fusillades.
But a greater evil of the present system becomes more and more marked; namely, that in a system based on private appropriation, all that is necessary to life and to production — land, housing, food and tools — having once passed into the hands of a few, the production of necessities that would give well-being to all is continually hampered. The worker feels vaguely that our present technical power could give abundance to all, but he also perceives how the capitalistic system and the State hinder the conquest of this well-being in every way.
Far from producing more than is needed to assure material riches, we do not produce enough.

Private notes, quoted in G. E. Fasnacht, Acton's Political Philosophy. An Analysis (1952), p. 60, n. 1
Undated

Interview with Al Jazeera (25 May 2018)

Wallerstein (1979) The Capitalist World-Economy. p. 15.

Vol. II, Ch. XX, p. 474 (See also...David Ricardo, The Principles of Political Economy and Taxation, Ch. VII, p. 81).
(Buch II) (1893)

Source: Intuitions and Summaries of Thought (1862), Volume II, p. 105.

Source: Watchmen