"People too often forget that IQ tests haven’t been around that long. Indeed, such psychological measures are only about a century old."
Yeah, because other metrics of human mental performance, or any kind of psychological property of humans for that matter are so much older than a century, right ? A century in psychometrics, is 13.5 billion years in physics, to make the "dog-years" analogy.
Reality: IQ is the oldest, best, and most solidly established predictive metric of success. In fact it's pretty much the oldest metric anyone bothered keeping at all (presumably exactly because it works, it seems very unlikely to me that it just happened to be the first one they tried. I remember studies that tried to quantify "nobleness" and "noble blood" in people and correlate that to intelligence for example).
Back to the article. The source for all this wisdom ?
(This book essentially makes the point that there is a lot or variability at the extreme outliers of genius. Even then, it is forced to conclude that while those extreme outliers weren't the very top geniuses at a young age, they were very smart. The just weren't top of the top early in life, even though they did become the top of the top later in life. It points out the corollary: genius increases the odds of success, which is very different from guaranteeing it)