The U.S. seems much like the late Roman Empire in this sense. Whereas the growth and expansion of the Roman Empire was fueled by its wars and conquests, which brought back slaves and material wealth, the American Empire's growth has been fueled by skimming off the top of the middle and upper classes wherever there's been socioeconomic troubles elsewhere.

The U.S. can get away with policy inefficiencies like this because there's so many people who want to get in right now, and it actually works in favor of the Powers That Be, because they can get decent talent that's easy to "keep them in their place" because of said policy inefficiencies.

That having been said, the U.S. doesn't going blowing stuff up in Europe to make this advantages happen. For a lot of people, it is a beacon of opportunity. It's not all blue skies and roses though.