That’s debatable… even with increasing poverty, the US still is by definition, mostly a labor aristocracy, which has a very specific and concise definition:

The labour aristocracy is that section of the international working class whose privileged position in the lucrative job markets opened up by imperialism guarantees its receipt of wages approaching or exceeding the per capita value created by the working class as a whole.

And while its true that wages have gone down in the US (certainly not to the level of the average world working class tho), cost savings from imperialism are more than enough to offset the loss in wages.

A good section from John Smith - Imperialism in the 21st century:

Neoliberal globalization has transformed the production of all commodities, including labor-power, as more and more of the manufactured consumer goods that reproduce labor-power in imperialist countries are produced by super-exploited workers in low-wage nations. The globalization of production processes impacts workers in imperialist nations in two fundamental ways. Outsourcing enables capitalists to replace higher-paid domestic labor with low-wage Southern labor, exposing workers in imperialist nations to direct competition with similarly skilled but much lower paid workers in Southern nations, while falling prices of clothing, food, and other articles of mass consumption protects consumption levels from falling wages and magnifies the effect of wage increases. The IMF’s World Economic Outlook 2007 attempted to weigh these two effects, concluding: "Although the labor share [of GDP] went down, globalization of labor as manifested in cheaper imports in advanced economies has increased the ‘size of the pie’ to be shared among all citizens, resulting in a net gain in total workers’ compensation in real terms.

In other words, cost savings resulting from outsourcing are shared with workers in imperialist countries. This is both an economic imperative and a conscious strategy of the employing class and their political representatives that is crucial to maintaining domestic class peace. Wage repression at home, rather than abroad, would reduce demand and unleash latent recessionary forces. Competition in markets for workers’ consumer goods forces some of the cost reductions resulting from greater use of low-wage labor to be passed on to them.

In his study of Walmart, Nelson Lichtenstein reports: “Wal-Mart argues that the company’s downward squeeze on prices raises the standard of living of the entire U.S. population, saving consumers upwards of $100bn each year, perhaps as much as $600 a year at the checkout counter for the average family… ‘These savings are a lifeline for millions of middle- and lower-income families who live from payday to payday,’ argues Wal-Mart CEO H. Lee Scott. ‘In effect, it gives them a raise every time they shop with us.’” Lichtenstein, 2005, Wal-Mart: The Face of Twenty-First-Century Capitalism (New York: New Press).

Perhaps the most in-depth research into this effect was conducted by two Chicago professors, Christian Broda and John Romalis, who established a “concordance” between two giant databases, one tracking the quantities and price movements between 1994 and 2005 of hundreds of thousands of different goods consumed by 55,000 U.S. households, the other of imports classified into 16,800 different product categories. Their central conclusion: “While the expansion of trade with low wage countries triggers a fall in relative wages for the unskilled in the United States, it also leads to a fall in the price of goods that are heavily consumed by the poor. We show that this beneficial price effect can potentially more than offset the standard negative relative wage effect.” They calculate that China by itself accounted for four-fifths of the total inflation-lowering effect of cheap imports, its share of total U.S. imports having risen during the decade from 6 to 17 percent, and that “the rise of Chinese trade … alone can offset around a third of the rise in official inequality we have seen over this period.”

You’re right that the labor aristocracy arose through historical processes and will eventually disappear through them. The disappearance has probably already begun. It looks like the US labor aristocracy is slowly proletarianizing.

But I disagree about how far along this is. I don’t see real proletarian demands or outlooks from the white working class, such as open borders, opposition to US police and the military, seriousness about global warming, solidarity across race and gender, etc. They’re still acting like a labor aristocracy.

The view of the Comintern and Lenin was that the US had a proletariat by the turn of the century though.