The Purpose of Mixed Economies

We've talked about free market economies and command economies, but the truth of the matter is that nearly every country on Earth utilizes a mixed economy, which blends aspects of each of the aforementioned economy types. Whether talking about the United States, European nations, or almost any other country, economies utilize aspects of a free market but also some government control. What is the purpose of this approach? Why should a government get involved in an economy? Why is this model so successful? Let's find out!