> You had to become a king, and then constantly murder people trying to take the throne

There’s a bit more to it than that. There’s a reason Xi Jinping doesn’t need to murder members of his cabinet all the time. A stable government has a winning coalition which keeps the leader in power. The leader has to keep them happy which in small enough governments he can do by paying them directly.

In a democracy, the winning coalition is way too large to simply pay supporters. The government has to fund public works which are more cost effective. A larger winning coalition is better for the median person for this reason.