Could be due to my work, but I picture it as an optimization strategy. Mostly (60%?) keep doing the same proven things, and have some of the population underta

Could be due to my work, but I picture it as an optimization strategy. Mostly (60%?) keep doing the same proven things, and have some of the population undertake risky but promising endeavors. This way you keep exploiting the local maxima, but explore around it. Not having everyone follow the same strategy can be a nice safeguard against extinction, I can see how it could be selected for. Cooperation isn't always the way to go for survival, especially when resources are scarce. I wouldn't say "nature" favors one or the other. There's room for both, and one or the other will be better for the individual depending on the context. Individual survival has repercussions on species survival, thus can be selected for. Plus, if everyone is all-in on cooperation, anyone can come in and extract massive benefits from not playing by the rules (and vice-versa). Thus there is always a niche for both strategies: picture merchants vs local economies for instance.