Uninspired votes count just as much. Pollsters have at times had a problem with this. One reason you see huge swings in Gallup polls is because they base so much of their likely voter model on “enthusiasm.”
In non presidential years enthusiasm can be a big deal (1994, 2006, etc.) as many presidential election regulars stay home, but for presidential elections past electoral behavior is a much better guide than enthusiasm. In other words a person who has voted before but says he isn’t enthusiastic is still more likely to vote than someone who hasn’t voted before who says he is enthusiastic.