(a) you are missing the point, this is as much to say that home purchasers were more likely to be wealthy in 2006. It isnt a valuation that is independent of time or context, and couldn't be a measure of human 'intelligence', whatever that means. And (b) just leads to a tautology, which again is my overall point: IQ measures things that are valuable in a specific context and time period, designed by members of the same group.