I never got that argument. First of all we have smaller units called states which can carry out policy. Secondly if we are ten times as large and have 11x the wealth and resources what difference does it make?
Our massive poverty, kept in place by the supposed war on poverty, and ghettos is the problem. But we could over come that.
However , I'm not sure anyone is saying we should adopt their ways. Merely that ways other than ours can work.