Having spent my childhood in one of the poorer corners of the globe, it tracks with what I experienced, for what it's worth. When folks don't have much, group sharing any bounty received, and being the recipient of others', is how people survive.
So yes, you see cooperative behaviors in the poorest of communities. Because other behaviors at that income level are incompatible with life!
In the long run, non-collectivist populations develop an advantage through hard times and environments. Collectivist populations subsist, and nothing more.