Maybe the problem is that ever since google the only metric anyone has bothered to devise is "popularity", which was never a particularly good indicator of truth to begin with.
Otherwise you could easily buy your way above Wikipedia, a non-profit organization (Wikimedia) - which ranks at or near the top for every query.
Quora, or some other VC backed knowledge service with a couple hundred million to vaporize, would overtake Wikipedia through the direct purchasing of popularity. Then others would quickly follow, entirely wiping Wikipedia from the first pages. That can't be done. If it could, private equity via Answers.com and other such very low quality sites would have already done it, seeking billions of dollars in return on such positioning.