In the USA, we do not even use the same college entrance exam in all higher ed systems. Different state systems use different exams, and then so does each private college and university. There are several, and which you take (or you may take several) depends where you are applying.

It's also not one exam, in the sense that it gets held multiple times a year and retaking it (if you're willing to pay for it) is possible and a lot of people do it and submit their best scores.

The SAT & ACT are also mostly limited to the humanities and math (and science for the ACT), with an optional writing section. China requires Math, Chinese, a foreign language, and any three of Physics, Chemistry, Biology, Geography, Politics, and History. With the SAT all those elective subjects are separate exams and most people do not take them.

I think another big factor is that past a certain point university prestige doesn't really matter in the US. In East Asia a lot of stock is put into reputation of university that you get into, but the well of decent American universities that get you good job prospects is much deeper.