With survival pressure, most people die. See that Alone show, most people get at best 2 months done and then thats even before the harsh of the winter really sets in. Just hard to establish enough systems to bring in your daily caloric needs without anyone to help you. You really need the tribe to make survival actually manageable. And in tribal societies all over the world we see how delegating the needs of survival has lead to a lot of other benefits, such as time to iterate on cultural ideas.