USA culture will be forgotten when the present empire falls. How much Prussian/ German culture do you consume? Prussia was considered a high watermark for culture, but nobody seems to care about it anymore. And y'know? Good. Because countries who are violent, imperial, oppressive? Their culture deserves to be forgotten.
Yeah, American Christmas is pretty much entirely derived from German tradition: Santa, gifts, Christmas trees, lights, carols, etc.
So much of American food derives from German food: hot dogs, pretzels, hamburgers, modern beer (hopped beer and bottom fermentation of lagers were both invented by Germans, and are now the dominant form of beer globally).
And as America exported all of these cultural traditions, those still derive from German immigration to America to begin with.
The English language itself still has strong Germanic influence.