As I recall, one of the ideas of the Frankfurt School was that the working class had become integrated into capitalism, and therefore was no longer revolutionary.
I think there's some truth to that. In the 18th and 19th centuries, and to some extent the early 20th, you see a lot of descriptions of industrial workers as a despised social out-group, and I think that was a significant aspect of working class militancy.
This is not to say that workers are privileged, but that they are integrated.