"Differences of age and sex have no longer any distinctive social validity for the working class. All are instruments of labour, more or less expensive to use, according to their age and sex. No sooner is the exploitation of the labourer by the manufacturer, so far, at an end, that he receives his wages in cash, than he is set upon by the other portions of the bourgeoisie, the landlord, the shopkeeper, the pawnbroker, etc. The lower strata of the middle class — the small tradespeople, shopkeepers, and retired tradesmen generally, the handicraftsmen and peasants — all these sink gradually into the proletariat, partly because their diminutive capital does not suffice for the scale on which Modern Industry is carried on, and is swamped in the competition with the large capitalists, partly because their specialised skill is rendered worthless by new methods of production. Thus the proletariat is recruited from all classes of the population."
Obvious this is mutatis mutandis: Marx was thinking of child labor and not age discrtimination; nor did he give proper attention to sex discrimination in employment. He failed to foresee the rise of Payday Lending and the kind of debt settlement sharks discussed in LBO135's excellent article on bankruptcy. And now it's not just the lower strata of the middle class, but all sectiuons of the middle class whose fall into the proletariat because their skills have been devalued. The last sentence is the one on which to place emphasis. What economist, was it Kondratiev?, called Marx the great anatomist of the capitalist system? I read that quote in Horowitz's edited collection of essays on Marxian Economics from back wbefore he, in the language of the Walking Dead, turned. But I have no easy access to the book right now.