In the May 18 Science, Philip Tetlock reviews Scott Page’s book The Difference, and basically nails it: Casual readers could easily conclude that Page .. has clinched the argument for the egalitarians. Indeed, Page arguably invites the interpretation that there may be no awkward efficiency-equality tradoffs when he repeatedly declares that "diversity trumps ability." … In brief, diversity appears to trump ability – at least when we equate high ability with drawing lucky starting points in sharply constrained searches for solutions. But elitists will argue that the game was rigged.
Scott Page's position provides a strong argument for democracy - always have a bunch of alternative parties hanging around, out of power; they may hit on the truth, and be needed later.
You write as if there's only one "point of prediction markets". Incentives are certainly important, but why should they be the only motivation?It sounds plausible that the wisdom of crowds is an important contributing factor to the accuracy of prediction markets. It would be nice to see good evidence for or against that.
See The Error of Crowds for one of my own disagreements with Scott Page.
Wouldn't more diversity increase the chance that someone knows the answer and is confident enough to make a bet and also increase the chance that there are ignorant people willing to take the bet? In other words, improve chance that someone will have the answer and increase incentive for them to reveal the answer.