I'm a bit wary of "giftedness" in intelligence discussions... I think the author's argument is very weak, analogous to: "Scientists have identified thousands

I'm a bit wary of "giftedness" in intelligence discussions... I think the author's argument is very weak, analogous to: "Scientists have identified thousands of parameters influencing the efficiency of petrol-powered cars. Each parameter seems to influence the outcome by a small amount. If we simply chose the best value for each parameter, I predict that we could see cars with efficiency in the range of 500 miles per gallon". A related argument (I think the one you are making) is that generally optimising one thing is going to trade off other things. So going all-in on fuel efficiency might impact crash resistance, for example. The author's argument for general intelligence might be true if the basic architecture of our brains has a lot of room for improvement. This might be true, but it seems that evolution should have already exploited any low-hanging fruit. This whole thing reminds me of the "humans only use 10% of their brains" flavour of reasoning.