Apart from debatable (but real) genetic differences you don't know about, the crucial point is culture. We're not cave people as we don't share their culture and don't have to.
Your idea of our environment predisposing us for capitalism is simply false. Notably, the premise rests solely on your posturing here.
Your ideas about people being automata beholden to their genetic programming beyond their control is even more absurd. And lacks any basis in evidence.
You apparently have never heard about ethics. There is a difference between morals and ethics. Lying isn't wrong because "arbitrary morals" say so, it is because realistic, objective consequences tell you so.
Your idea of an "equilibrium of all behaviors" presupposes mindless automata, again.
Human societies are meta-organisms - they modify themselves over time, and compete with each other for finite resources. Any culture which sacrifices competitive advantage for any reason is simply out-competed and absorbed by other societies which make no such sacrifice. There is no escaping this reality. This is referred to as cultural group selection.
> Your idea of our environment predisposing us for capitalism is simply false. Notably, the premise rests solely on your posturing here.
I'm not saying it predisposes us to capitalism though, I'm saying it predisposes us to maximize resources and engage in competitive behaviour. This is supported by the fact that very nearly every organism in nature also engages in resource maximization and competitive behaviour (r-Selection). There is no altruism (going against genetic self interest) in nature, it's simply not sustainable.
> Your ideas about people being automata beholden to their genetic programming beyond their control is even more absurd. And lacks any basis in evidence.
I'm making no such claim. I'm simply claiming there are constraints in the system, and ignoring them doesn't make them go away.
> Lying isn't wrong because "arbitrary morals" say so, it is because realistic, objective consequences tell you so.
Any yet, no matter how hard we try, we've not managed to eliminate lying (or even agree what specifically it means). Are you really suggesting that some yet-undiscovered set of rules will create a society in which no one will ever lie? Doesn't that sound a bit.. unrealistic?
Because that is, in a very fundamental and immutable way, who we are.
I'm saying that we live in an ecosystem, and that creates emergent properties and behaviours. Resource hoarding and interference competition are among those. No amount of consciousness, rational thought, or foresight, can change that.
As long as (e.g.) hoarding resources today makes it more likely for your offspring to succeed tomorrow, the traits that influence people to hoard resources will continue to perpetuate. It's also why, for example, we have the dark tetrad - it works.
Too high of trust creates opportunities for liars. Too many liars lowers trust to the point that it's not profitable to lie. There exists between these two points a stable equilibrium between zero liars and everyone lying all the time, and it's at neither extreme. The same is true for all other behaviours you moralize.
I'm not justifying anything, I'm simply observing the constraints of the system we live in, and inferring that any mode of social organization that ignores or opposes these constraints is doomed.