Unfortunately it is the free market that creates monopolies. As a corporation grows and becomes too wealthy, it just buys smaller corporations that compete with it or prices them out of the market. In a free market (which does not exist) there would be no laws/policies to prevent this from happening.

In a free market over time monopolies are naturally created because there is nothing to stop them. Even in a somewhat free market, as we see in the USA today this can happen via crony capitalism and corporate takeover of the government. Corporations and the wealthy people that own them start either creating or eliminating government laws/policies that interfere with their revenue, by buying/funding/bribing politicians.