I used the word prosperity and not growth for a reason. Even though e.g. China has a very high growth, Chinese people are not very prosperous yet. Their quality of life isn't great. The goal of the economy is to provide people with products, and those products improve the quality of their life, that's all. There is no unlimited growth, simply because can we can't have unlimited people on the planet.
Your bread and games argument is absolutely true. People can be okay with any kind of political authority, even if it's Pinochet, as long as their needs are satisfied. The moment they get hungry though, instability rises and all hell breaks loose. My point is that nation-states are not well-equipped at all to deal with current world issues because they are too small and can rarely organize actions together. Hence yes, the nation-state structure if inefficient and does not bring as much prosperity as could be possible otherwise.