We should be skeptical that any particular metric does what it claims to do, especially ones which are ad-hoc or based on intuition instead of evidence. I'm not suggesting that Gladwell is wrong about any of the examples he gave being 'mismatches', or that there are many of them, and exposing the misuse of metrics is certainly valuable. However, he seems to go further, suggesting that we can't find good predictors at all, which is a claim which I think deserves just as much skepticism. I doubt he would seriously make such a claim, and it is probably just an artifact of an early talk which won't be present in his book, but I have plenty of skepticism to go around, so I'm perfectly happy to deploy it wherever it is warranted at all.