A city - let alone a province, nation, continent or planet - cannot live in the form of anarchy. Those who are powerless seek the protection of those who have power, this in turn allows those with power to gain greater influence and power, and so on. Capitalism isn't really better or worse in this regard, it just defines what form power takes - in this case, wealth. And as always, those who have power will use it to gain more power.

Overthrowing a system to replace it with another is initially better, because the new system does not have the centuries of accumulated corruption weighing it down, but it will inevitably reach the same state. Overthrowing a system without a replacement just leads to the new form of power being the basest of all - survival.

In anything larger than a small, tribal unit, authority is necessary to prevent the anarchy that would tear the civilisation apart, but that authority will inevitably work to ensure its continued existence, and the betterment of its own operations through increased power. Bane overthrew the old order, but the new order was the right of might, with Bane and his tanks as the rulers.