As the article mentions it's only 70k years ago that we start seeing unambiguous indicators of intelligence. The normal figure for this indicator, the upper paleolithic revolution, is 50k years. In any case that's where we first start seeing significant and then rapidly widespread signs of intelligence - fishing, extensive adornment, wide artifact collections, burial ceremony, and much more.

The point here is that the archaeological record seems to indicate that it's like one day we simply 'woke up.' Whomever was fortunate enough to experience such a mutation first would have had a tremendous competitive advantage. The degree in intellectual advancement is such that they would have probably been significantly better at just about everything -- most importantly in surviving and spreading their genes. Now take this person and what would likely have been their vast number of offspring. They could effectively take over the world. And I suppose, in a manner of speaking, they did.