There are many ways to control people.
One could threaten physical harm. That might work on a personal level- one to one.
One might offer great rewards for subservience. That too might work on a personal level.
But take the masses, where there may be dissenters, whatever the threat, whatever the reward.
How then, should we deal with this problem?
Debt; control debt, you control the money supply, you control the people.
It is not about money- it is about lack of money- debt.