Natural selection is slow and results in many variations of a theme, for example there is a wide variety of monkeys. It's not possible that this same wild natural process was the main driver of the evolution of modern humans. There is insufficient evolutionary pressure in nature to explain why we so quickly developed intelligence far in excess of that needed to find food and shelter. Cynics have a valid point that we couldn't have happened naturally by the same process as all other plants and animals. There are evolutionary scientists that do have a handle on it, but the popular idea that we are 100% natural is not helpful to understanding who we are and how we came to be.
I think there might have been a tipping-point crossed when the brain achieved a certain capacity. Of course, cultural aspects were critical to catalyse this phenomenon, which is evident when you examine remote tribes such as those in the southern Nicobar islands, who are anatomically modern humans, but behave more or less like advanced orangutans.
A sort-of runaway event that lead us to be what we are today. Nonetheless, natural selection is very much in play here. By ‘natural’ I include those actions that human individuals influenced, as well. We are a part of the natural world.