Nobody said anything about not having governments. Rule of Law is required for societies to even exist.
Read some more on the robber baron era - you'll find out Standard Oil was already losing to competition before government action. For another great example how the free market broke a cartel, read up on how Dow Chemical fought the German bromine cartel:
Please don't put words in my mouth. Government's role in a free market economy is quite essential: upholding rule of law (specifically contract law) and taxing externalities. Overreach is the problem though (like regulating the charging port on my damn phone).
Read some more on the robber baron era - you'll find out Standard Oil was already losing to competition before government action. For another great example how the free market broke a cartel, read up on how Dow Chemical fought the German bromine cartel:
https://en.wikipedia.org/wiki/Herbert_Henry_Dow#Breaking_a_m...
No government intervention necessary.