Generally speaking, the average American Ph.D. is less capable and less broadly educated in their field than the average German Dr.rer.nat. Specialization occurs earlier in the US, the time is shorter and many more people of only medium talent pursue a doctorate. Most Ph.D.'s become college teachers with minimal research tasks; such teaching jobs are much rarer in Germany.
http://math-www.uni-paderborn.de/~axel/ ... #diligence
US PhDs (frame of reference : archaeology) are more nearly technical specialists than people at the summit with an overview of their field and the way it relates to other fields. Which makes their generalizations decidedly parochial.