Ours is a critical time in the cultural evolution of humanity that is likely to shape our long-term future, or lack thereof. As a species, we have been on
If you want a detailed look on the topic, there's "The Dawn of Everything: A New History of Humanity", a book by Graeber and Wengrow, which also talks about the huge diversity of social models in old communities of humans.
It's impossible to say what prehistoric people were thinking or wanting. You can only look at how they lived their lives, or how later peoples organized their society. The main thing is that there isn't one way of living, some societies were hierarchical and probably materialistic based on grave goods and burials, some societies clearly had prosocial tendencies based on remains of people with disabilities showing care and nourishment.
All societies must necessarily be prosocial, it's how our species evolved to survive, just like prosocial tendencies are necessary for ants.
But that's different from saying we didn't evolve to be selfish like the post's article claims. Humans are always trying to get what they themselves want, even if that's just a drink or a blanket to keep warm.
I’m not convinced by any mass society that is altruistic, but it’s very simple to see that the natural state of human small groups is quite communal.
What mother has a ledger for the child’s share of food?
We have an entire feeling brain that’s dedicated to relationship building that’s very much the core of most small group relationships.
I’m also very convinced that this model does not work past Dunbar’s Number (~100-150 individuals), and most attempts at building communal society outside of that without some cohersion and some better way of organizing incentives is not possible.