> Game theorists are always asking why people vote, because the likelihood that you are going to be what we call a pivotal voter—a voter that changes the election—is basically zero. Yet still people are participating.

Is this really an open question? It sounds simple to me. Your vote raises the likelihood that someone from your party becomes the pivotal voter by a tiny amount. It's like increasing your share on a pie chart when someone is blindly shooting at it and the color that gets hit wins. People care about their candidate winning, not about personally deciding the election.