I think the comment you are referring to is employing hyperbole to make a point. It is not accurate to say the British Empire "ruled the world" (just large chun

I think the comment you are referring to is employing hyperbole to make a point. It is not accurate to say the British Empire "ruled the world" (just large chunk of it) nor that Britain is a small island no one cares about now. The point is that it has gone from being an economic and military super power to being a second tier power. The point is these things change over the long term. In a hundred years from now it is likely the super powers will be different - most likely China and India, simply because of their size.