Real money inherently has a limited supply, so there is no need for it to be managed or controlled; the market does that on its own. However, the fiat currencies that are used by central banks around the world are not real money. The arrogance of central banks thinking they can manage and control the economic interactions of millions of people in a country is what leads to these great depressions and recessions.
> The arrogance of central banks thinking they can manage and control the economic interactions of millions of people in a country...
The arrogance of physicians thinking they can manage and control the biological interactions of billions of cells...
Just because something has a lot of moving parts doesn't make it intractable. "Complex" is just latin for "put together", and we can always try to take it apart, learn about individual parts, and work our way up.
In any case, not doing anything is also a decision. It's a completely arbitrary idea–as if monetary policy were some sort of intrusion into the "natural law" of the economy.
Physicians don't think they can manage and control the billions of cells in our bodies; we still don't understand how all of our cells even work. Physicians apply tested practices to individual people and hope that it addresses whatever medical problem is being observed. They understand that treatments are not one-size-fits-all and that mistakes can kill people. They also understand that our bodies self regulate and they are only trying to address a specific imbalance in their specific patient, not something that applies to an entire population.
Central banks think they can turn a couple of knobs (currency supply and interest rates) and control an entire economy made up of millions of people. Using the physician example, that's like thinking that the only two treatments needed for any medical condition are adjustments to our blood level and body temperature.
Monetary policy is a newer invention in the history of human civilization and even then, it wasn't always applied so universally. Monetary policy can only exist with central banks.
Fiat currencies do not have a limited supply and are therefore not a store of value (i.e., inflation constantly lowers the value of fiat currencies). The main reason that fiat currencies are still used as a medium of exchange is for the exact reason you mentioned: governments mandate their usage to pay taxes.
As an example, gold and silver have been used as money for 1000s of years because they meet all of those requirements.