Memes

That's not enitirely true. The American Dream was (and is) settler-colonialism. Early settlers were promised free land if they killed indigenous peoples living there already, which led to a mostly self-sufficient labor class that could use its self-farmed land as a means to support themselves while bargaining for higher wages. If you were a white man, this dream was attainable, period, even if it meant enslaving and genociding millions of people.

Then came the post-war period. The wartime economy was still fairly planned, and aimed at full employment. Further, the US was emerging as world hegemon and de-facto empire. Imperialism and social safety nets largely expanded due to needing to provide better metrics than the Soviet Union was providing again kept the white men of the US living in the American Dream.

Now that imperialism is decaying, and social safety nets have been gutted along with the fall of the USSR as the main rival power, even white men are starting to fall into genuine proletarianization at large. The US is still a settler-colony, but its one where finance capital has dictatorial control yet imperialism is waning, and where many industries have been hollowed out and shipped overseas because imperialism was more profitable. The US is working its way to its own demise.