In other words, all being taken into consideration, it turns out IQ has an incredible predicting power regarding the lives of individuals. It's actually better at predicting life outcome than any other factor.
> And, of course, nurture over nature [...] matters way more than genetics.
That is the opposite of what current research into IQ has shown so far. If you go on YouTube, you can find interviews with Charles Murray, and that will help you understand this better.
> A good musician can become a good sharpshooter, a good programmer can excel at architectural engineering.
Yes, but it's not likely to happen (or you'd have oodles of examples). Predicting is all about what's more likely, and in this capacity, IQ has proven over and over again to be the single best predictor.
I'd understood that the best predictor of success at a job is Conscientiousness. More than test scores, economic class, fancy schools.
Average, above average and higher scoring persons' outcome in life will depend more heavily on upbringing and surroundings than anything else.
In fact, those scoring the highest may actually end up worse - addiction, depression, anxiety, loneliness, etc. - all because they live well below their potential because of their circumstances...
Being a good writer - what does that mean? Someone who has had some real, interesting experiences may be a better writer than someone who is wired to tell good stories.
Physical features also matter - a lot. Your brain may be perfect for a nuclear physicist, but you're no good if you're gonna have a stroke or heart attack suddenly on the job.
And, of course, nurture over nature - people's background, how they grew up, how they were educated from their first year to now, matters way more than genetics.
If you don't/can't account for all of that (and more) when deciding a person's future, then keep this science to yourself.