Rome fell, or rather the Western Roman Empire fell due to:
Extension of citizenship was continuously done throughout Roman history -- from Alba Longa to the Social Wars (extending citizenship to all of Italy), then to Hispania and Cisalpine Gaul, then under Caracalla to all of the Empire (expanding the tax base)
English might be at its base a Germanic languages, but 70% of its words are French/ Latin/Italian/Spanish in origin. And English grammar follows the French fashion of dropping of cases -- if it was really a Germanic language it would have 5 cases instead of 1 today (Nominative, Genitive, Locative,Dativa,Vocative)
So English IS descended from Latin to a large extent as well as from proto-German (I call it a bastard language :)
It is a Germanic language from the Anglo-Saxons, with some Latin grammar infused in it. While it is a “bastard language” (which makes it very difficult to learn), it is very different from a Romance language.