I don't think it's just the moderators, there's also an incentive problem because a popular question/answer has no limits on its point-payout.

This leads to a kind of popularity gold-rush pattern. Hard important stuff languishes while easy stuff is has a glut of volunteers.

I'd be interested to see what happens if questions and answers only gave up to a fixed limit of Internet-points to the authors or contributors. Would it lead to a broader knowledge base?