Two important things; EU hasn't bowed their heads to the US supremacy otherwise things like "Germany buying gas from Russia" would have never happened. Second, the "American Supremacy" is a false term by itself, if America had supremacy then there would be nothing to worry about, right? You see, the world is not as simple as you guys think, it's not all about US, China, Russia only.
Lastly, the US is doing a lip service to the EU countries since it needs European thecnolagy more then EU needs US-lead world order.