Several stories in the Torah pivot on ordinary characters. Joseph seeks his brothers and “a man from Dothan” points the way, thus furthering the course of history. The spies in Joshua’s time are hidden by Rahab, thus ensuring they return safely.
We too often assume the great are the only ones who make a decisive difference in the world. It takes a Lincoln, a Napoleon, an Alexander — or a Newton, an Einstein — to change the course of human events. But Citizen Drouet was a modest French provincial who, by dragging a cart across an arched gateway near the bridge at Varennes, foiled the attempt of Louis XVI to flee Paris. In June 1914, a young Serbian nationalist named Gavrilo Princip killed Archduke Franz Ferdinand and precipitated World War I. Repeatedly the world is changed not by the exertions of genius but by the initiative, good or bad, of otherwise unknown people.
One of the frustrations and glories of action is that we cannot know the ripple effect of what we do. Exertions for good should never be seen as wasted; causality is complicated and a mitzvah may change the world for better in ways we cannot imagine.