Why are there so few American-born scientists?

It is not that there are fewer American-born scientists. To paraphrase China's hot words, the appearance rate of American and foreign scientific and technological representatives (top scientists) in the news media can't be the same. It is precisely because top scientists from all over the world gather in the United States that fewer scientists were born in the United States, but in fact, even foreign-born scientists in the United States received higher education in the United States and finally stayed in the United States.