Like most Americans, you're provincial and apparently unaware of developments in the rest of the world. Those people weren't coming here seeking out American Capitalism. They were running away from the excesses of European Capitalism, the same "unrestrained private enterprise" that not only made Fascism, Anarchism and Bolshevism possible, but made it inevitable. European capitalists were ahead of us by a few years, they just got there first, but otherwise they weren't that much different from our own robber barons.

There was revolution throughout Europe in 1849, and they weren't revolting against any shortages of capitalists, read up on the Paris Commune. There was the Franco-Prussian war in the 1870s and widespread conscription was in place. Europe was a cesspool of poverty and depression and war, due precisely to the stresses of rapid industrialization, urban crowding, colonial rivalry and the excesses of its capitalists.

America was at peace except for the Civil War, and expanding into the Western Frontier. That's why people came during the 19th century. The country was exploding industrially and geographically, and it was underpopulated. There was free land, and soon, a railroad to take you there. That's why we were hiring here. Look at the chart. When did the Frontier close, the 1890s? Just about the time immigration started to naturally decline.

BTW, the word you wanted was "zenith", not "nadir", of unrestraint. The robber barons essentially had a license to steal.

You are also neglecting to factor in the effects of two world wars, the depression, and most important, the anti-immigrant legislation of the 1920s. That is why immigration falls "under control" after those years and settles down to a steady growth on a per capita basis. The New Deal had nothing to do with it, and I never claimed it did. THe social reforms I mentioned followed the Gilded Age, and were made necessary because of it.

Go back and reread that Teddy Roosevelt Square Deal speech again. You might believe him, he was a Republican. The term "Gilded Age" is deliberately ironic. For most immigrants and industrial workers, it was hell. I know, my grandparents came here in the early years of the 20th century. Cuba was recovering from its revolutionary war, it was devastated. It's the only reason they came.