right. one less barbarian than the other.
But more militarily ruthless than the other and, unlike the Visigoths, almost totally destructive of Spain's civilization of the previous 900 years.
The Visigoths of 711 A.D. were not Grandpa's Visigoths that had conquered Roman Spain. By 711 A.D., the descendants of those Visigoths had become complacent, weak and degenerate. It was only a matter of time before they were going to be absorbed into oblivion by Spain's Hispano-Roman population as they indeed soon afterwards were in the northern Spanish Christian Kigndoms.
Today's America, not unlike the case of the late Roman Empire, is not Grandpa's World War II America. An ever growing percentage of our population is becoming weak and degenerate. It is not inconceivable that, in a few generations when most of America thinks like Sheryl Crowe, America may fall to a more backward society that is not anaphylactically allergic to the art of war.
The future conquerors of America may be more than one and one may be more "cultured" than the other. However, that would not erase the civilization that was America in it's prime and it would not precluded a new American generation, steeled with resolve by adversity, from taking America back and restoring America's original culture.
Such was the case in Spain.
Your desire to have the Muslims invent civilization in Hispania because they may have been slightly higher up in the barbarian scale than the Visigoths were in 711 A.D. would be like claiming that the Mexican chapter of the Crips "brought civilization" to America in the year 2073 after the Mexican Crips had militarily overthrown the Islamic Republic of America that had been established by Middle Eastern Islamist clerics after America's defeat during President Chelsea Clinton's Administration.