I disagree. I have no idea why anyone in their right mind would underestimate USA even after they have proved again and again why they are the most dominant superpower in the world in the long-term.
I'm one of those people who don't like the US government one bit, but there's no denying that they are superpowers and they will continue to be the hegemon of the world for many years to come. Russia or China are still not strong enough to surpass them both economically or militarily.
But the balance of power in the world is becoming more and more balanced with the emergence of the BRICS bloc, a direct counterpart of the EU. This will make the world more balanced and will not depend so much on the US and the EU.