No, I hold an accurate view of them.
Differences matter and the difference between two Han Chinese is not the same difference between a White person and a Somali refugee no matter how much you pretend it is.
America was not always a multi-cultural society. It was a society for the white man. This was explicitly stated by every president from George Washington to Abraham Lincoln to Woodrow Wilson. Our frontier spirit was largely driven by claiming land for the white man away from supposedly barbaric and inferior races. Go read a history of the Mexican-America war if you want to dive into how much racial solidarity played a part in us winning that war. You like others want to make it seem a lot less homogeneous than it was by talking about Irish and Italian immigrants (of which I am one).
Similarly, China is not a multi-cultural society and neither is India. I'd encourage you to actually go to these places. When I went to India I had to stay in a barricaded hotel with bomb checks. I had people requesting to get a picture with me as I was so unusual every time I went out.
And as for why I think America was successful at innovating earlier in the 20th century? I think it has a huge part to do with a tremendous culture of education and learning, as well as huge amounts of investments.
Just to give an example, the Apollo project was 2% of GDP! Just think about that. Can you imagine research investment happening at that level?