Prediction markets work much better than polls. This is because those who know are willing to bet on it, and those who do not are (rightly) reluctant.[1] Some such as Tetlock have (plausibly) claimed they can do even better than prediction markets, but not by listening to random commenters with no skin in the game.[2]
TLDR; Talk is cheap, and people are much more careful with their wallets than their mouths (or keyboards).