I don't know when you last came here, but I would say a significant number of Black Americans don't resemble the typical West African. It's impossible to put a percentage on it, but there is a significant number...
You are right about how the legacy of slavery shaped race here...
I would also point out that identifying with blackness is more popular here, we "took back" our blackness sooner than South American nations, who are just now experiencing some of the black pride movements that we adopted in the early to mid 20th century. So that helped shape race over here as well, and I think even compared to some blacks in European nations, there is a different level if pride and acceptance in being black here. And I think that should be commended, because our black pride here certainly isn't for lack of systemic oppression, the same oppression that subdivided black and brown and other colorist ideals in Brazil and other South American nations you mentioned...