You're missing the point. There's a fundamental difference between doing what you're good at for the benefit of the tribe and doing what you're good at for your own personal benefit, refusing to share with the tribe unless they agree to your terms.

The former is sharing, the latter is trading. And again, there's no evidence that trading ever occurred in that situation. As another commenter mentioned, in the life-or-death scarcity of hunter-gatherer communities, you'd be punished or exiled (which would mean death) for modern capitalist-style selfishness. There's no commodification.

Also, knowledge and skills were shared. There were no trade secrets, no patents. It would be have been extremely dangerous for one person to be the exclusive source of an essential good. Again, specialization is a luxury of abundance.