Europe at least has had the benefit of being able to work country-by-country, whereas the US is one massive tangled morass. Hell, even achieving the kind of restructuring and harmonious cooperation that you see in the EU had to come as a result of two of the most atrocious wars humanity has ever mustered in the span of less than half a century.
Kinda puts it a little more into perspective when you consider the absolute shit-show Europe had to turn into before it was ready to grow up.