The argument in the stimulus tells us that overarching historical trends are overlooked -> parallels are overlooked-> lessens our ability to learn from history. The true reason our ability to learn from history is diminished because the overarching historical trends are overlooked not because the details of historical events are studied. The argument leaves open the possibility that it is possible to study the details of historical events and also pay attention to overarching trends, thus we cannot conclude that simply studying the details of historical events is sufficient to conclude that the ability to learn from history is diminished.