>Marxism is the most impactful ideology of the history of the 20th century

I agree. What a disaster that was! Let's hope it will have much less impact on the 21th century.

Are you ignoring the rest of the comment?

Most professional economists IMHO would not agree that Marxism's vocabulary permeates their field.

Core economic concepts are things like elasticity of demand, market equilibrium, externality, market failure, network effect, opportunity cost and comparative advantage, and AFAIK Marx and his follower had essentially no role in explaining or introducing any of those.

I think if you had read Capital, you'd find many of these concepts amply addressed, usually with different terminology.

Please list terms in this different terminology that are equivalents or analogs of the terms I listed, so that I can use Ctrl+F to find them in my PDF of volume one of the book.

Here's deepseek's answer. To Deepseek I add: Market failure is addressed even more in Lenin's "Imperialism: The Highest Stage of Capitalism" which addresses market and financial consolidation in the early 20th century (it's worse now). I would also add that Marx built off of and sometimes critiqued Adam Smith and Ricardo, it's not an entirely different branch of the intellectual tree.

    Elasticity of Demand – Marx does not explicitly discuss elasticity, but he analyzes demand fluctuations in terms of "the social need" (gesellschaftliche Bedürfnis) and "effective demand" under capitalism (Capital, Vol. III). He notes how capitalist production responds to demand shifts, though not in the formalized neoclassical sense.

    Market Equilibrium – Marx critiques the idea of equilibrium (a key concept in classical and neoclassical economics), instead emphasizing "anarchy of production" and "tendential laws" (e.g., the tendency of the rate of profit to fall). He sees markets as inherently unstable due to contradictions in capitalism (Capital, Vol. I & III).

    Externality – While Marx doesn’t use this term, he discusses "social costs of production" (e.g., environmental degradation, worker exploitation) as inherent to capitalism’s drive for profit (Capital, Vol. I). His concept of "metabolic rift" (in Capital, Vol. III and his ecological writings) touches on unintended consequences akin to negative externalities.

    Market Failure – Marx’s entire critique of capitalism can be seen as an analysis of systemic "failures," such as "crises of overproduction", "underconsumption", and "disproportionality" between sectors (Capital, Vol. II & III). He attributes these to contradictions in the capitalist mode of production rather than isolated market inefficiencies.

    Network Effect – Marx does not discuss this directly, but his analysis of "general social labor" (the socially necessary labor time underpinning exchange) and the role of "commodity fetishism" (Capital, Vol. I) implies that value is socially determined in a way that could loosely parallel network effects (e.g., the more a commodity is exchanged, the more its value appears natural).

    Opportunity Cost – Marx does not use this term (rooted in marginalist economics), but his labor theory of value centers on "socially necessary labor time", implying that the cost of producing one good is the labor diverted from other uses (Capital, Vol. I). His concept of "alternative employments of capital" in Capital, Vol. III also touches on trade-offs.

    Comparative Advantage – Marx critiques David Ricardo’s theory of comparative advantage (e.g., in Theories of Surplus Value), arguing that international trade under capitalism exploits unequal exchange and reinforces imperialism. He focuses on "uneven development" and "super-exploitation" rather than mutual gains from trade.

Marx permeates economics like Newton permeates physics.

If this seems like an absurd comparison, I would suggest reading both Philosophiæ Naturalis Principia Mathematica and Das Kapital.

The obvious and actual analog to Newton is Adam Smith.

Marx builds on Adam Smith and Ricardo among others and contributes an understanding of where money comes from and where profits come from among other things.