J_B to that I can only respond - again without a link!
While European countries will remain rich in terms of per capita income (about $32,500), their relative weight will decline with their demographics and weaker growth (on average, almost half as much as the United States)...The increased weight of [faster growing European countries like Ireland] will not...be sufficient to compensate for the retreat of its historic champions [britain, France, Germany] who will feel the full weight of their society's declining demographics... [And while there remain concerns about the United States' twin deficits,] because the United States will remain the world's superpower for the next two decades, the dollar still has some beautiful days ahead of it, remaining the key international reserve currency, so American budget deficits should remain under control, can be financed, which should avert a major international crisis.
Deutsche Bank Group