I missed technology and science in my list of things, but yeah that too.
If we use Nobel prizes as a metric, then US beats other countries by a wide margin in everything except Literature. (Surprisingly Germany and UK, the old world leaders still come close second, but then we ARE considering nobel prizes awarded between 1901-2014). In terms of per capita, US is ranked 19th, and UK, the only large country in terms of population ranks higher.
It's true that USA is world's third largest populous country, so in terms of absolute numbers it beats other nations hands down, but there are two things which need to be considered. If EU was a single nation with single language and no immigration restrictions, then you will get the same benefit of being in EU(400+ Nobel prizes) as much as you'd get of being in America(350+ nobel prizes), that is, more integrated intellectual networks. But EU is fragmented into different nations, and despite of being an open border, the linguistic and cultural disparities do fragment the number of people you could have been connected to.
Second point is, almost all major figures in art and literature in America have lived in NYC at some point or the other. This usually means that if you lived in NYC, there are future nobel laureates living here with whom you might be interacting. So I think that not only you need to be in America in order to access the biggest network effect of anything, you need to be in one of the larger cities like NYC or SF.