I have not seen many monopolies that have emerged absent of government interference.
Standard Oil emerged with the help of government?
There have been relatively few monopolies because of government controls. Left to themselves, corporations would ALWAYS engage in collusion to restrict the market because they could make more money by collusion than participating in a free market.
Classical free market economic theory almost totally neglects the rise of the "limited stock" company, i.e. the corporation. The idea that a business enterprise could accumulate the capital, political clout, and worldwide influence of modern corporations was considered totally outside the "realm of possibility".
When someone can cheat, someone will cheat.