Per Neill Massello:

A better track record is your best argument. The fact that money is
involved doesn't really mean that much. The millions wagered represent
the sum of many small bets rather than a few large ones placed by savvy
investors.

Dunno if guessing the odds of a candidate winning are analogous to
guessing the number of marbles in a jar or the weight of a bull - but in
those cases something seems to be going on with the aggregate of many
guesses: https://en.wikipedia.org/wiki/Wisdom_of_the_crowd
--
Pete Cresswell