A free market can lead to a monopoly, but they rarely last. The free market builds and destroys, hence its brilliance. State-sanctioned and state-acknowledged monopolies last because regulation creates barrier to entry. With no barrier to entry or exit the long term profit of a monopoly is zero.
Under Capitalism markets dictate the vast majority of the production throughout the world
And people dictate markets. You fundamentally misunderstand economics because you missed some important foundations of free market capitalism.