Check out Marcuse's 1969 "Essay on Liberation":
"By virtue of its basic position in the production process, by virtue of its numerical weight and the weight of exploitation, the working class is still the historical agent of revolution; by virtue of its sharing the stabilizing needs of the system, it has become a conservative, even counterrevolutionary force. [...] In the advanced capitalist countries, the radicalization of the working classes is counteracted by a socially engineered arrest of consciousness, and by the development and satisfaction of needs which perpetuate the servitude of the exploited. A vested interest in the existing system is thus fostered in the instinctual structure of the exploited, and the rupture with the continuum of repression - a necessary precondition of liberation - does not occur."