What nonsense. The Blues were not imported, it started here just like Bluegrass, Country & Rock n Roll. (<-———AMERICAN CULTURE)
By the way, having a defined culture doesn’t mean the absence of foreign influence. Japan is doing just fine without displacing their own people. They take the good & keep out the bad.....like rational, thinking people.
"Started here" doesn't mean it was "invented here".
Almost all modern forms of music were fusion of music from other cultures, imported into the US.