On the competence of American commanders in World War II

I've been reading Peter Schifferle's America's
School for War: Fort Leavenworth, Officer Education and Victory in World War II.
Generally I found it kind of dull, feeling a bit like a biography written only
about what a person did between 9 and 5 every day.

That
said, I was intrigued and persuaded by his basic conclusion: Senior American
commanders were much more competent in World War II than in World War I, he
says, especially in the difficult art of coordinating the combat arms
(infantry, artillery, armor, aviation) to break through enemy lines and then
exploit that breakthrough. The reason for this competence, he says, was the
education they received at Fort Leavenworth in the interwar period. He quotes
the comment of German Field Marshal Gerd von Rundstedt, who after being
captured in 1945 reportedly said, "We cannot understand the difference in your
leadership in the last war and in this. We could understand it if you had
produced one superior corps commander, but now we find all of your corps
commanders good and of equal superiority."