Jazz. Blues. Techno. Ragtime.

Blues, Jazz and Ragtime all predate WWII — and all influenced pretty much everything you hear today.

You could even argue that Breakbeat is American given its roots with the Winston’s.

American culture is vastly richer than many countries specifically because it is effectively an All Star team of traditions from everywhere. Thinking “American” is simply hot dogs and Hip Hop is to greatly undersell what has been one of the great cultural achievements in the history of the world. American culture is vastly diverse compared to, for example, France. You have Cajun/Creole in Louisiana, Tejano culture in Texas, cowboy culture in Montana, laid back “surfer” culture in California, Boston/Nee England culture, Chicago with it’s melange of Polish, Italian, African American. Where else in the world could you have sushi for lunch and watch a rodeo in the evening? To be clear, I am not saying American culture is “best,” I am just saying that to reduce American culture to Hip Hop is about like saying French culture is nothing more than Edith Piaf and baguettes. Americans even invented basketball and baseball — and most of the things I mention were in motion long before world war 2.

NYC was a culture hub long before Workd War 2. Read some de Tocqueville and learn a bit about American history before just engaging in a wholesale dismissal of America.

I am not prone to quoting Bono, but this clip is relevant: https://m.youtube.com/watch?v=O8aLAZ8SnvI

Appropriation and disproportionate credit for white people is a real and serious problem, but it's not the whole story. Most of the actual musicians who were inspired by black music fully acknowledged their inspirations and were often annoyed at how no one seemed to care about the people they looked up to.

The actual artists out on the stage doing the music know exactly what comes from where. Culture spreads like that: someone likes a piece and adds it to their own, fusing two cultures. It's how we have American Chinese food that looks nothing like Chinese Chinese food. (the xenophobic policies that led to it is another matter)

You have a very narrow and stereotyped view of American culture. The whole of it is not a few white-majority cities in the north and one over-funded region in the west.