You're just restating what I said with just more words. But, you don't propose an alternative simulation model.
I would say that the simulation is actually generous. Wealth is correlated with power. Power creates opportunities for exploitation. I know of very few examples where this is not the case.
The alternative simulation model would allow transactions to create wealth or destroy wealth.
Wealth is correlated with power but that power is not necessarily only directed against other rational actors but the environment and circumstance, too. So it makes sense to see power as an increasing or decreasing value overall with time.
100% power in 1500 A.D. is very different than 100% power now (if percentage of power makes sense at all considering how dependent it is on circumstance).
The other thing about power is that there are power singularities. If I can cause the death or pain of another as part of a transaction either actively (gun to the head) or passively (they will starve without the transaction taking place), that person will spend almost any amount of value to avoid that fate. This kind of exploitation should be taken into account.
Power does not always, or even most of the time, create opportunities for exploitation. If someone has some base level of power to avoid the singularities as described above they can have transactions with more powerful entities that are not exploitative at all but of mutual value gained benefit.
Hitting a perfect zero sum game is a very simplified case and only useful as a rough approximation because most transactions are merely /close/ to zero sum with some value add otherwise the market would rush in to narrow the gap.
So, a more interesting model would take both the creation and destruction of wealth into account as well as the opportunities for exploitation (since, while those are not the bulk of transactions, in today's world they are still incredibly common).
This would be more interesting because it would show 1) how various levels power changes over time beyond the relative measure and 2) how prone each group is to exploitation.
If certain conditions lead to the lowest tier group having increasing power over time and reduce their exploitation potential but lead to large increases in the gap of relative power, that would be a much better outcome than if they have less overall power and are in more exploitable conditions but their gap of relative power is smaller, for example.
I would say that the simulation is actually generous. Wealth is correlated with power. Power creates opportunities for exploitation. I know of very few examples where this is not the case.