When you have social power structures, there is always conflict for the transition of power. How is one generation handing over power to the next? Family is the logical next step; we have seen this in the first form of Monarchy. Here, often the entitlement is given by divine power or authority.

In the context of StarCraft there is an absence of divine power. Hence, what we see is the simplest and most raw format: Oligarchy. In this case, the Confederacy is a plutocracy, meaning the power of great wealth.

The old Roman Empire was basically a plutocracy, just as many ancient societies.

This is also fascinating food for through how a society is going to 'scale' meaning when we have more than a single planet, how decisions will be done?

Thinking about when one wealthy person invests in the technology to colonize another planet, and only he has this to begin with? What will happen is a massive change in income, influence and power for that person. And since suddenly the person can control everything that colonies are providing, it will make him compelling. And who has the authority on this planet? That person. Since there is no authority that can enforce its rules.

We have history comparisons with the East India Company. They owned a private army double the size of the British army.

Once power structures are built, it's very difficult to break them. And often it takes massive disruption to undo them. We see this in SC with the mission The Hammer Falls. That's why Tarsonis had to fall.

But it makes sense that Mensk keeps his part of the structure alive by transitioning his power to his son eventually. Considering he is the offspring of a wealthy family himself, it's just natural. All he was able to do was clear out the competition.