The US would have thrived on any system because it started the game with a continent whose indigenous population was small, pluralistic, nomadic and technologically backward, and whose natural resources were abundant or completely untouched. The colonists had access to the technology of the leading power in the world at the time, and had imported slaves in bulk from another technologically backward continent to jump-start their economy by the time the US was established.

Doubt. Arguably the US thrived because it is too far from Europe for their wars to cause too much devastation. Unregulated industrialization also gave us child labor, 12h days, 6d work weeks, and company scrip.

After WW2 the US stood alone and enacted a lot of socialist ideas. Then spent a few decades slowly erroding those worker rights and sensible regulations in favor of corporate interests.

That seems a bit reductive; I don't even know that you're "wrong", but there are a lot of factors that might have led to the United States' success. We have a lot of natural resources and a lot of our land is readily habitable.

Yes, the US also has relatively liberal economics [1], and maybe that's why the US has done well, but I think there are too many confounding variables to conclude it's purely because of economic liberalism.

[1] I mean liberal in the academic sense, not as a synonym for Democrat.