Actually, yes, we would have lost. We would have had our asses handed to us, like a hat. It was an unknown type of warfare, in an unknown, and ancient land, fought by a people who had a deeper cause, then just beating an enemy...they had pride in their ideals and beliefs. We didn't learn in Korea either, which is why we didn't learn in Vietnam, which is why we are working our asses off now, fighting against another unconventional enemy, that uses tactics and methods we are unfamiliar with. Things have changed since Pearl Harbor, and The Battle of the Bulge.
Our modern military is doing much better now, and at least they train, and have advanced by leaps and bounds...but we still fight politically correct wars, with targets picked by lawyers...when our enemies don't. It's hard to make that work. But they are trying, and do a pretty fucking outstanding job, considering the limitations our leaders put on them.