What "middle class"?
The phenomenon of the great American "middle class" is an invention of the 1960s. Prior to then, the majority of the American public, greater than 60 percent, considered themselves to be working class.
The term "middle class" was reserved for the people who actually happened to be in between the great mass of workers and the small elite political-capitalist class.
Just from reading late 19th century/early 20th century literature (I mean the kind they have you read in standard texts in high school) it seems obvious to me that the ability to hire servants--not legions of footmen and scullery maids to be sure, but one or two--a housemaid, a governess, a handyman--was a taken-for-granted hallmark of the true middle classes of that time, even in America. Quite obviously these people weren't the ruling bourgeoisie, who did have legions of servants, just for their homes, while commanding veritable armies of employees at work (which they owned). A middle-class American of the decades between the Civil War and say the 1920s would ideally be neither an owner of enterprises that employed lots of workers nor someone else's employee. They'd be independent professionals if urban--doctors, lawyers, people like that. Or own a medium-small business--not a mom-and-pop store, but not one with more employees than they personally knew and interacted with daily either. Out in the country they'd be the more successful farmers, owning lots of land and employing a number of hands.
Fast-forward to the end of the 20th Century and you can see how the continuity is broken; there are plenty of people with the money to hire household help all right, but we wouldn't consider them "middle-class;" we'd call them "rich." They are still subaltern rich, not the big shots. But now, to have that sort of income you must almost certainly be someone's employee. Just a very well-paid one. But such people no longer have the sort of independence that was a basis for arguing they should be the backbone of the political system and the standard for judging the national interest. Now they are beholden to the hand that feeds them.
Meanwhile the idea of "middle class" has been shifted downmarket; mainly as a way of dividing the working class as much as possible. Below a certain point a person can't seriously consider themselves "middle class" by even our modern cheapened standards but people still cling desperately to the status because admitting to being something less than that is admitting total irrelevance to the status system and being despicable. But the newly downshifted "middle class" that can't even hire a nanny is pretty much just as irrelevant to and despised by the real classes that matter in the decision-making of the nation. Flattery keeps it that way; with cheap, empty words the working class never unites and recognizes that essentially, taken together, they
are the people and these pretentious upper classes should be supported and tolerated exactly to the extent they make the common people's lives better, and no more. That awakening can never happen as long as we cling to this "middle class" idea, and we always will as long as we fear falling more than we feel confident we can, with solidarity, stand on our own.
I believe Jello is pointing out, once upon a time not so very long ago, Americans had a shrewder idea of where they stood on the food chain, and if the upper classes did not deliver acceptable policies, they had the peculiar notion they had some right to step up and deliver some policies of their own. American socialism, such as it was (and it was quite a lot, in certain places and times, in various forms) was what happened when some of those working class people decided the time had come, or was perhaps long past, to stand up and start actually doing something about it.
The myth of the middle class in its modern form is part of how US society smothered that movement. That was an example of a carrot; there were also sticks.
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Oh, and I think the evolution of this modern notion of the middle class may have culminated in the '60s, but it was a work in progress long before then. A lot of American mythology--I am thinking here of movies in the 1930s--involves a fusion of the world of working-class people with the very rich. In the mythic world of the silver screen, you often would see rich and poor learning to hobnob with one another. The stubbornly snobbish rich could be made fun of, as could the irredeemably boorish poor, but the moral of the story was often that at the end of they day, the best people from each class could get together.
There were other movies from those years though that tend not to be remembered so well, and they paint a starker picture. They aren't the ones that would get shown in the middle of the day on the cheaper TV stations though.