Terry Tao turned out well - but he's just one of many.
I know one guy that finished his Bsc in math by age 17, and got accepted to Cambridge - he's a rich fund manager today. Didn't really contribute to science, but interests change with time.
The number of kids featured in such articles is really a drop in the ocean. So, coming to the conclusion that 'having a gift is not synonymous with being successful' is not entirely correct.
As a counter example, Zuck, Sergey Brin and Lady Gaga were identified as talented youth. They may not have been covered by the Economist when they were kids. But all of them are certainly successful in my book.
1. being successful and famous are not the same thing
2. being famous at an early age is probably correlated with wanting to be as far away from the public eye as possible as an adult, if any other options are there.
But also, I was in one of those articles (a long time ago and am now an Old in internet time), so AMA, I guess.
From time to time, we see articles like this of a gifted children.
And then we never hear from them ever again.
It seems to me that having a gift is not synonymous with being (moderately) successful.
Am I totally biased, wrong on this notion?