It would be more accurate to say that value of 15X to 225X their aggregate earnings was created via a path that happened to include Brin and Page at a key point. It would be an error to, for example, suggest that this means if we went back in time and... used some crude intervention to prevent Brin and Page from contributing then we could expect a result of an earth in 2013 that contains 9 trillion less in value.

See my response to elharo. I agree that $9 trillion is too high.

I suspect that this estimate of value creation while interesting is rather likely to be used with misleading connotations. For example using it in a naive manner would result in 'altruistic' decision making that is grossly miscalibrated with respect to actually increasing expected value.

Do you think that I misused it in the present context? In giving my estimates I was attempting to strip out the altruistic component.