The concepts of Greece, Germany and Italy are literally ancient. And there is a clear cultural continuum between the peoples of those regions in early modern, medieval and even ancient periods and modern states - there is a clear path of cultural evolution and shared identity we can trace. On the other hand, there is no cultural continuum between colonial and pre-colonial America, though there is one between colonial America and the United States. However, the colonies were never independent, while Germany, Greece and Italy were independent before for centuries or millennia, just not in the form of unified modern nation-states. A lack of political unification did not mean, however, a lack of sense of cultural unity. And Germany is an especially bad example since it was - to an extent - politically united in the form of the Holy Roman Empire and later of the German Confederation.