They can be wrong. The problem is that you are looking at a single data point. Judging their performance requires viewing all of their predictions, across all e

They can be wrong. The problem is that you are looking at a single data point. Judging their performance requires viewing all of their predictions, across all elections, and seeing how often their predicted probabilities match up with outcomes. Do the people they give a 30% chance of winning win 30% of those races? Do the people they give a 60% chance of winning win 60% of those races? That is how you judge their performance, and from that lens they do quite well.