So what? Good for China. The US doesn't have the right to the world's largest economy. More and more economies are global, individual countries don't matter anymore. This won't be detrimental to the average American and as the standard of living rises in China hopefully, their population will start to decline, since they don't allow immigration
China is the worst choice to be the global economic super power. Any cursory check on how they treat the Tibetan, Mongolians or the Ugir Muslim would give even Hitler nightmares. But I remember being in school in the late 70's when I was suggested Japan would surpass the U.S. Japan economy went into the doldrums in the late 80's and today the Chinese dragon is starting to sputter out out also.