“Gen. Mark Clark, commander of U.S. forces in Italy, explains how gutting his forces in Italy in the months before D-Day stalled Allied progress against German forces.”
Myopia. Its actually the other way around. Italy sucked up supplies, landing craft, aircraft, soldiers, etc. Ike thought without the Mediterranean theater looking so large, the landings in France and a straight drive into Germany could have happened as much as a year earlier.
The British soldiers were first class. But their leaders prolonged the war. Market Garden is another example. To placate Monty, that failed Holland attempt at an end run stripped Patton’s army and stopped them for months.
The war in Europe could have ended even as much as a year earlier were it not for the British political leadership.
Much of what I've read about Monty is he did not trust the intel coming down from ULTRA/Bletchley Park. In the North Africa campaign Monty would be told that Rommel would be at a specific location and he would not act on it fearing the intel was bad. This happened many times I've read and it would totally frustrate Churchill.
I've read that if Monty had acted and attacked Rommel would have been destroyed and the whole European theater would have been won at least a year earlier.