Why is the ethnic composition of the United States mainly Anglo-Saxon whites?

The view that the United States is an Anglo-Saxon country is not based on the absolute proportion of ethnic groups in the population, but on the social resources and power possessed by ethnic groups.

When the United States just became independent, if we exclude nearly 20% of the total population in terms of population composition (the proportion in the south can be as high as 40% or more). British immigrants account for less than 70% of the white population, while immigrants from England only account for 40%; If we look at the new immigrants, in the three-quarters century before 1776, the largest proportion of the population imported into the United States (whether voluntarily or not) was African blacks.

But obviously no one will think that the United States was a black country when it was founded, because the ethnic groups with a high proportion of the population may not have high economic conditions and social status; Similarly, among the white population, Irish immigrants, who are not less than English people, have long been discriminated against because of their religious beliefs and other reasons.

And a large number of German immigrants who settled in Pennsylvania were also very unpopular in the early days of the founding of the People's Republic of China. For example, Franklin was very critical of the German phenomenon in Pennsylvania (even now, there are still minority media talking about Trump's German identity).

The dominant position of British-Americans (based in New England and Virginia) in domestic affairs during this period can be clearly seen, which can be seen from the family origin of the founding fathers of the United States.