But this all follows from an unsubstantiated assumption. The thread isn't about how we should structure our society if certain innate differences are in place (which is what you are talking about, but that's a whole thread of its own, and a political one at that, because there are many issues beyond maximizing total utility). The question on the table is, what innate differences have been established, as distinct from environmental influences that we ourselves are responsible for? My answer to that is quite direct: none, in the areas of adult reading and math skill. Then all one has to do is note the potential harm in confusing our own handiwork for innate differences (a common outcome that is called "prejudice").